Chris Chinn, of Deep in the Game (one of the best RPG blogs around), recently wrote a post entitled An exercise for the viewer at home.

In it, Chris excerpts a snippet of text from the intro to Exalted that reveals a lot about the assumptions underlying that RPG. I love this idea (thanks, Chris!), so I’m going to try it here in a slightly different form.

I went through 30+ RPGs and wrote down their definitions of the GM’s role — and found a range of definitions, from appalling to marvelous (including some that will make you wonder how so many people ever got into GMing). With reader contributions, 97 games are now covered on this list.

First, a few notes about this list.

It’s not a representative sampling of every possible “type” of RPG, by any means! But there is quite a bit of diversity in terms of publisher, genre, era and approach. (Update: It has quickly become a lot more comprehensive, thanks to reader contributions!)

Along with the publisher’s name, I’ve included two things with each entry that can be pretty telling: publication date, and which page the definition came from (as well as the number of pages in the book, not counting blank pages or ads at the end).

Many RPGs go through several different editions, and even when I have multiple editions they aren’t all included here — because the most interesting differences are between the oldest and newest editions. (I also included Vampire, but not Werewolf or any of the other Storyteller games, for pretty much the same reason.)

How 30+ 97 RPGs Define the GM’s Role

Advanced Dungeons & DragonsPlayers Handbook, 1st Edition) (TSR, 1978)

The game is ideally for three or more adult players: one player must serve as the Dungeon Master, the shaper of the fantasy milieu, the “world” in which all action will take place. […] A good Dungeon Master will most certainly make each game a surpassing challenge for his or her players. […] The Dungeon Master must design and map out the dungeon, town, city, and world maps. He or she must populate the whole world, create its past history, and even devise some rationale for what transpired (and will probably happen). (Pages 7 & 8 of 128)

Advanced Dungeons & DragonsDungeon Master’s Guide, 2nd Edition (TSR, 1989)

Being a good Dungeon Master involves a lot more than knowing the rules. It calls for quick wit, theatrical flair, and a good sense of dramatic timing, among other things. (Page 7 of 192)

Adventure! – Core book (White Wolf, 2001)

[T]he Storyteller is a “director” of sorts. The Storyteller acts as a combinanation narrator and referee, creating the drama through which the players take their characters. As a Storyteller, you create the environmnet in which the characters are placed. You are responsible for tying the story’s disparate threads together and making sure the whole thing runs smoothly. Your most useful tools in balancing story and game are your imagination and the rules systems. (Page 107 of 272)

All Flesh Must be Eaten – Core book, 1st Edition (Eden Studios, 1999)

To enforce the rules and provide a coherent setting, one of the participants assumes the role of Zombie Master (called Game Master, Chronicler or Referee in other contexts). (Page 20 of 231)

AlternityPlayer’s Handbook (TSR, 1998)

The participant in the game who acts as moderator, narrating adventures and representing other characters involved in the adventure who aren’t controlled by the players. (Page 9 out of 245)

Amber – Core book (Phage Press, 1993)

This is the person who controls the “world” and runs the game. All the non-player characters (NPCs), including guards, innocents, and villains are controlled by the GM. The GMs [sic] control even extends to things like weather, cross-universe politics and natural disasters. (Page 9 of 256)

Ars Magica – Core book, 4th Edition (Atlas Games, 2000)

No definition provided. (272 pages)

Batman Role-Playing Game – Core book (Mayfair Games, 1989)

The Gamemaster is like the writer of a Batman comic book, unfolding the story and making it work. The GM also has the important task of playing the roles of all the other Characters in the adventure. […] The Gamemaster writes down the basic framework of the story, drawing out plans for the various locations, assigning abilities to the villains, and creating the special plot twists that might occur. The GM must have a good grasp of the rules of the game, because he or she is the one who conducts play and acts as a referee. (Page 5 of 192)

BESM d20 – Core book, Revised (Guardians of Order, 2004)

No definition provided (192 pages)

Bubblegum Crisis – Core book (R. Talsorian Games, 1996)

One of you will take on a different role, that of the Referee (or Gamemaster, or GM): the person who presents the story plot to the players, controls any characters not controlled by the players themselves (logically called non-player characters), and applies the rules of the game. […] The Referee uses the background given in the gameworld to devise a basic plot into which he places the player characters. He describes the situations to them as the characters would know it and the players describe what their characters are doing and how they are responding to the situation. The plot generally flows from there, with the Referee presenting obstacles, non-player characters, and other elements to the players in story form and the players continually deciding what their characters will do and reacting accordingly. This way both the players and the Referee create a story together…and have a lot of fun along the way. (Page 18 of 168)

Bunnies & Burrows – Core book (Fantasy Games Unlimited, 1976)

Rather, there is a Gamemaster (GM) that oversees the game, designs the playing area, is expected to modify the rules given herein to suit his or her fancy, and is the only omniscient participant in the game. (Page 1 of 74)

Burning Wheel – Core book, Revised (Burning Wheel, 2005)

In Burning Wheel, it is the GM’s job to interpret all of the various intents of the players’ actions and mesh them into a cohesive whole that fits within the context of the game. […] He has the power to begin and end scenes, to present challenges and instigate conflicts. […] Most important, the GM is responsible for introducing complications to the story and consequences to the players’ choices. (Page 268 of 303)

Call of Cthulhu – Core book, 2nd Edition (Chaosium, 1983)

A game moderator, known as the Keeper of Arcane Lore (“Keeper”), is necessary for this game, and his role is to attempt (within the rules of the game) to set up situations for the players to confront. […] …a game moderator who runs the world in which the adventures occur. (Page 5 of 96)

Call of Cthulhu – Core book, 5.6 Edition (Chaosium, 1999)

The player who acts as keeper becomes the game moderator. Perhaps using a published scenario, or creating on of his or her own, the keeper knows the entire plot of the story and presents it during play, incidentally taking the parts of all the monsters, spooks, and sinister or ordinary people that the investigators meet. (Page 24 of 287)

Castle Falkenstein – Core book (R. Talsorian, 1994)

One of you will become the host, a player of the Great Game who has all the good parts: judge, jury and creator of the fantasy world everyone else will share. As Host, it will be your job to pose the Situation that all the Players will become involved in… […] As Host, you have a lot of tools at your disposal: you’ll get to create all the characters the other platers don’t, (including the parts of the Bad Guys), using them to shape and create the adventures you conceive. (Page 134 of 224)

Chivalry and Sorcery – Core book (Fantasy Games Unlimited, 1977)

No definition provided. (128 pages)

Code of Unaris – Core book (Gold Leaf Games, 2004)

A gamemaster wears many hats. She narrates the story, plays the parts of any fantasy personas the players meet, handles rule adjudication, and usually takes a lot of grief from the other players when things don’t go their way (and that’s the good part). (Page 114 of 314)

Continuum – Core book (Aetherco/Dreamcatcher Multimedia, 1999)

The game master has designed the scenario — or purchased a pre-written one — which the player characters will play out, and the non-player characters are essentially his levers within the story, with which he can seek to guide the plot. (Page 213 of 224)

Cyberpunk 2020 – Core book, 2nd Edition 2.01 (R. Talsorian Games, 1993)

No definition provided. (254 pages)

Dangerous Journeys1: Mythus (Game Designers’ Workshop, 1992)

As an impartial and disinterested participant in the story, the GM serves both to help and hinder the player group. The GM lays out the scenario, provides information to the players, acts the roles of minor characters, adjudicates disputes between the players’ personas and characters they meet, interprets the game rules, and critiques play after the completion of an adventure by awarding merits to individual players for the skill with which they played during the game. (Pages 6 & 7 of 416)

The Deryni Adventure Game – Core book (Grey Ghost Press, 2005)

Gamemaster (GM): the person who runs the game for one or more players. The GM organizes play sessions; presents the game world usually through narration, although game aids like maps are often used; roleplays or acts the part of secondary characters and villains (called “non player characters” orNPCs); and determines the outcomes of any character’s actions within the world, usually through the use of dice as a randomizing factor. The GM serves as narrator, director, sound effects, and “extras” such as NPCs. (Page 67 of 254.)

Doctor WhoPlayer’s Manual (FASA, 1985)

…he moderates the game, keeping in mind and reinforcing the limits and rules of the game. Called the gamemaster, this player judges the effects of the player characters’ actions and determines what the response to those actions will be. He plays all the ‘bit parts’: the bystanders, aliens, villains, and other characters who are not central to the action but who interact with the players’ characters in some way. […] He is responsible for making the game run smoothly so that all have a good time. He guides the action so that the players will succeed — but only after making a number of important decisions and only if they work hard and play their roles well. (Page 3 of 48)

Dogs in the Vineyard – Core book (lumpley games, 2004)

You’re the GM, though, and that means you don’t have just one character: you have everything else. You play all the supporting characters and antagonists, you have final say over the imaginary sets where the action happens. You set the pace, push the characters into conflict and crisis, and describe the consequences of their decisions. […] For instance, it’s never the GM’s job to plan what’ll happen. The GM’s job is to create a town at a moment of crisis (which I’ll tell you how to do in good detail) and from then on, only respond. (Page 2 of 101)

The Dominion Tank Police – Core book (Guardians of Order, 1999)

A typical role-playing scenario requires a handful of players and one person to run the game, known as the Game Master (GM) or referee. The players tell the GM what their respective characters would like to do throughout the course of the adventure scenario and the GM describes the results of their actions. When the GM works closely with each and every player, the game adventure remains exciting and fun for all. (Page 14 of 176)

DragonQuest – Core book, 2nd Edition (SPI, 1982)

The GM is a master story-teller, a weaver of tales which deal with those themes aforementioned: fairy tale, myth, and fantasy. […] While the players act out the parts of their characters, the GM gets to act out the parts of everyone else who inhabits the world — shopkeepers, evil wizards, dragons, and giants. Along with playing these parts, the GM is the referee of all the actions which occur; his impartiality is assured by the absence of a game persona directly identified with him. (Page iv of 156)

DragonQuest – Core book, 3rd Edition (TSR, 1989)

There are many other characters and monsters, all of whom are operated by the gamemaster. The gamemaster is a combination of referee, storyteller, and “Hand of Fate.” He keeps the story unfolding by telling the players what is happening and judging the results of any actions the players take. He has a very free hand to interpret the situation as he sees fit within the guidelines of the rules. (Page 3 of 160)

d20 Modern – Core book (Wizards of the Coast, 2002)

The GameMaster, as the director and special effects designer, decides what the story is about and takes on the roles of all the other characters — the villains, the extras, the distinctive guest stars. The gamemaster also keeps track of the rules, interprets the outcome of actions and describes what happens. Together, players and GM create a story and everybody has a great time. (Page 5 of 384)

Duel – Core book (Crunchy Frog Enterprises, 1992)

One person, the game master (or GM) sets the plot of the story, but the rest of the people involved provide the characters (known as player characters, or PCs) that are the heroes of the story. It is almost like a round-robin story telling session, but in a role-playing game, the GM has control over what happens. (Page 1 of 36)

Dungeons & Dragons – Core book, 2nd Edition (TSR, 1978)

The characters are then plunged into an adventure in a series of dungeons, tunnels, secret rooms and caverns run by another player: the referee, often called the Dungeon Master. […] The Dungeon Master designs the dungeons and makes careful maps on graph paper. (Page 5 of 48)

Dungeons & Dragons – Core book, 3rd Edition Bluebook (TSR, 1979)

The characters are then plunged into an adventure…run by another player: the referee, often called the Dungeon Master. (Page 5 of 46)

Dungeons & DragonsGame Master’s Guide 3.0 Edition (Wizards of the Coast, 2000)

Rather, you get to decide how your player group is going to play this game, when and where the adventures take place, and what happens. You get to decide how the rules work, which rules to use, and how strictly to adhere to them. […] You get to build a whole world, design all its characters, and play all of them not played directly by the other players. […] Since you control the pacing, the types of adventures and encounters, and the nonplayer characters (NPCs), the whole tenor of the game is in your hands. (Page 6 of 256)

Elric! – Core book (Chaosium, 1994) (Also the same in Stormbringer, 5th Edition)

The most fun in the game is had by the gamemaster. The player who acts that part moderates the game. Using a published scenario or one he or she has created, the gamemaster narrates the game universe and acts as the adventurers’ opposition. That opposition must be smart and mean, or the players will be bored, and it must be presented fairly, or the players will be outraged. (Page 9 of 162)

EverwayPlaying Guide (Wizards of the Coast, 1995)

[T]he game-master has to know the game, the setting, and the characters well enough to present an engaging plot and pace the action so that the plot unfolds dramatically. The gamemaster invents strange lands for the heroes to explore, exotic creatures for them to encounter, weird mysteries for them to solve, and daring quests for them to undertake. (Page 2 of 162)

The Fantasy Trip: In The Labyrinth – Core book (Metagaming, 1980)

The key to the game is the Game Master, or GM. The GM sets up the labyrinth which the characters will explore. He may even create an entire outside world for them to travel through! The GM referees the game, taking the part of Fate and the Gods. He (or an assistant) also plays the monsters, beasts, and other wanderers that the players will encounter. The Game Master is the final arbiter; he should strive to be fair, but his word is law. It is his task to keep balance in the game and to see that the players have a fair chance — and enjoy themselves! (Page 3 of 72.)

Farscape – Core book (Alderac Entertainment Group, 2002)

He or she serves as a combination of narrator, referee and supporting cast: he develops the setting and adventures, describes the environment and plot developments. and portrays any non-player characters (NPCs) the PCs may encounter. The GM also serves as an arbiter of the rules, enforcing the die rolls and making sure that the group maintains proper balance. He is, in effect, the director of the Farscape story which the group is telling: steering it in the right directions and giving the PCs the opportunity to play Hero. (Page 13 of 320)

Gamma World – Core book, 2nd Edition (TSR, 1981)

The referee is the participant who is willing to provide the mental and physical labor of completing the game within the framework provided. He will also preside over the actual play of the game itself. […] He must carefully balance risk with reward. The game he creates must not be so “deadly” as to make survival of the player-characters impossible. On the other hand, he must see to it that the player-characters are challenged. Too many rewards given at too little risk is sure to create a boring game. (Page 4 of 56)

Gamma World – Core book, 3rd Edition (TSR, 1986)

A role-playing game requires one player to play the role of the Game Master (GM for short), the creator and teller of the story and the arbitrator of the game’s events. The GM creates the goals and obstacles of an adventure and plays the part of all the creatures encountered throughout the story. It is a tough job, but one that is very rewarding, for only the GM knows what is really happening and what obstacles lie before the heroes. (Page 2 of 64)

Gamma World – Core book, 4th Edition (TSR, 1992)

No definition provided. (192 pages)

GURPSBasic Set, 3rd Edition, Revised (Steve Jackson Games, 1999)

The nature of the adventure is set by a referee, called the Game Master (GM, for short). The GM determines the background and plays the part of the other people the characters meet during their adventure. […] The GM describes the situation, and tells players what their characters see and hear. […] Depending on the situation, the GM may determine what happens arbitrarily (for the best possible story), or by referring to specific game rules (to decide what is realistically possible), or by rolling dice (to give an interesting random result). (Page 8 of 278)

GURPSCampaigns Book, 4th Edition (Steve Jackson Games, 2004)

The Game Master (GM) is the referee of a roleplaying game. But that’s putting it too simply. He is like a mystery writer…a storyteller…an umpire…a cosmic book-keeper…the “house” at a gambling casino…and (to the characters) a minor deity. […] The GM is the final authority. Rules are guidelines…the designers’ opinion about how things ought to go. But as long as the GM is fair and consistent, he can change any number, any cost, any rule. His word is law! (Page 486 of 576, but the Campaigns Book starts at p. 337)

HackmasterGameMaster’s Guide (Kenzer and Company, 2001)

The purpose of this book, after all, is to better prepare you for your role as game moderator and referee. […] As GM you are master of your table. The success of your own campaign is primarily in your hands and you must take a firm, active hand in guiding it. (Page 14 of 368)

HeroQuest – Core book (Issaries, 2005)

One person takes the role of the narrator who plays a wide array of narrator characters–everyone except the player heroes. The narrator also plays the world–tells what the weather is, how steep a mountain is, how suspicious a person seems, and so on. The narrator’s job is to place limits on the heroes, confronting them with entertaining challenges as they try to accomplish their goals. (Page 9 of 288)

HERO System – Core book, 4th Edition (ICE, 1990)

When playing a roleplaying game, one player takes the parts of the director and author. This person, called a GameMaster (GM for short), decides the basic plot of the adventure. The GM describes the setting to the players…The GM acts out the roles of all of the people the players encounter in the course of their adventures. (Page 4 of 220)

HERO System – Core book, 5th Edition (DOJ, 2002)

GM: Game Master — the director, referee, and arbiter of a roleplaying game session. (Page 8 of 374)

HoL – Core book (Black Dog Game Factory, 1995)

In agreeing to be HoLmester [sic], you have accepted multiple burdens:
1. Speaking to those writhing, whining, benumbed nematodes, the players, as though they had frontal lobes.
2. Inviting them to your house and trusting them not to urinate in the toaster.
3. Prostituting your thespian capacity for free pizza and liquid proteins.

NOT TO MENTION creating new player characters for all the bozos who creak down and moan about having to pick from the pre-gens. (Page 61 of 144, probably)

Hunter Planet – Core book, 2nd Edition (HPAC Australia, 1987)

The person running the game (called a CM in Hunter Planet) supervises all facets of the game from the character creation to the actual adventure itself. When characters are created, players confirm any points they think of with the CM when it arises. (Page 33 of 35)

In Nomine – Core book (Steve Jackson Games, 1997)

The GM must create the structure of the story (that is, write the plot, or adapt an existing adventure to his players’ characters), assume the roles of the NPCs, and describe the ongoing events as engagingly as possible so the players stay interested. (Page 27 of 208)

James Bond 007Basic Game (Victory Games, 1983)

The director is called the Gamesmaster (usually abbreviated as GM). The players will act out the parts of the heroes, and the GM will handle all the villains and minor characters (called Non-Player Characters, or NPCs). The GM creates the script, portrays all secondary characters, and acts as the final arbiter on the rules of the game — that is, the rules all have agreed to play by. (Page 5 of 160)

kill puppies for satan – Core book, 1st Edition (lumpley games, 2001)

No definition provided. (32 pages)

Legend of the Five Rings – Core book (Alderac Entertainment Group, 1997)

The Game Master (called the “GM”) is a vital part of the game. While each player creates a single character — the main characters of the story — the GM is responsible for creating the supporting cast the player’s characters encounter. He takes the role of every character the players meet and he devises a plot for the characters to participate in, improvising plot twists when the players decide to a different direction than the one he planned. He is the player’s senses, describing all the details of a scene. […] The GM is an author and improvisational actor, but he is also a referee. Whenever a dispute arises between players, the GM must use the rules (along with a good, healthy dose of common sense) to make a decision. (Page 8 of 250)

Lejendary Adventures Lejendary Rules (Trigee Enterprises, 1999)

The LM will determine the cosmic environment for game play. He or she will adapt and/or create the whole universe, direct and orchestrate all the events of the game’s worlds and the variety of environments found therein. […] It is the job of the LM to relate the campaign-specific information available to players, and relate to them all sensory data the game environment provides to their Avatars. […] The LM will also play the role of every person or creature encountered that is not directed by a player. […] Lastly, the LM will adjudicate all disputes as the final authority on the rules, award meritorious play, and manage playing time on a regular and agreed-to basis so as to provide the highest quality of entertainment possible for all participants the campaign. (Page 4 of 208)

Little Fears – Core book (Key 20, 2001)

Little Fears is written with the belief that the GM should be open to the suggestions and improvisations of the players and the players should be the same with regard to the GM. Together, everyone works to build a great story. The game-master is there to throw in adventure seeds and provide some interaction and the players are there to pick up which seeds they like and interact as well. (Page 64 of 137)

Living Steel – Core book (Leading Edge Games, 1988)

One person, the Gamemaster, acts as a sort of referee, moderating the adventure and portraying everything and everyone in the world that the characters encounter, and guiding the development of the plot. (Page 1 of 179)

Lord of the Rings – Core book (Decipher, 2002)

One member of your group is the Narrator, the person in charge of creating the outline of an adventure for your characters to take part in. She explains the situations and plays the parts of all the non-player characters (NPCs), anyone in the story that another player doesn’t control. She describes to you what your character sees, or what happens in the adventure. (Page 6 of 304)

Lords of CreationRule Book (Avalon Hill, 1984)

The Game Master (abbreviated GM) makes up an outline for the adventure. He invents the setting, and populates the adventure with villains, monsters, and other personalities. The GM also acts as a judge to make sure that game action flows smoothly and that everyone has a good time. (Page 3 of 64)

Macho Women With Guns – Core book, 3rd Edition (BTRC, 1994)

You are the GM, and in game terms that translates to complete godhood. It’s the only chance you’ll get, so abuse it to the hilt. (Page 41 of 68)

MechWarrior – Core book, 3rd Edition (FASA, 1999)

The gamemaster controls the story. He or she keeps track of what is supposed to happen when, describes events as they occur so that the players (as characters) can react to them, keeps track of other characters in the game (referred to as non-player characters, or NPCs), and resolves attempts to take action using the game system. (Page 6 of 223)

Metamorphosis Alpha – Core book, 1st Edition (TSR Rules, 1976) (Also unchanged in the 2002 version, James M. Ward’s Metamorphosis Alpha Universe)

The referee is that participant who decides he would enjoy running the game and is willing to accept the burden of drawing the starship levels and locating the life forms on each level as well as noting where the various technological items and/or new information is to be found… (Page 3 of 32)

Middle-Earth Role Playing – Core book, 2nd U.S. Edition (Iron Crown Enterprises, 1986)

The Gamemaster has been described as the limited “author” of the FRP game; actually, he functions as more than this. The Gamemaster not only describes everything which occurs in the game as if it were really happening to the player characters, but he also acts as a referee or judge for situations in which the actions attempted by characters must be resolved. […] He must develop the setting and scenarios for the play of the game, using the game rules, and either material of his own design or commercially available play aids. […] In addition, the Gamemaster plays the roles of all of the characters and creatures who are not player characters, but nonetheless move and act within the game setting. (Page 4 of 128)

MunchkinMunchkin Master’s Guide (Steve Jackson Games, 2003)

This is the book for the DM…or, as you may prefer to call yourself, the Referee, the Game Master, or God. This is the book that tells you how to use the power that is rightfully yours. Keep your players happy, if you wish…or abuse them like the helpless pawns that they are…you’re in control. (Page 5 of 48)

Mutants & Masterminds – Core book, 2nd Edition (Green Ronin, 2005)

One player takes the role of Gamemaster (or GM) and describes the setting and the challenges your characters encounter. The Gamemaster plays the supporting characters and villains in the story. The GM also acts as referee to adjudicate the rules of the game and make sure everything’s handled fairly. (Page 6 of 255)

Paranoia – Core book, 2nd Edition (West End Games, 1987)

In Paranoia, the gamemaster presents adventures for his players to enjoy. […] You pretend to be Everything Else — The Computer, the plot, the people who the Troubleshooters meet, all the world and everything in it. You also act as the referee for the game, judging whether or not players’ actions are possible or permissible. (Page 31 of 134)

Paranoia – Core book, 5th Edition (West End Games, 1995)

The gamemaster is a player, he just works under different rules than the other players. The gamemaster has more weapons, more tools, and more options than the other players but he also has a certain responsibility. He has to “run” the adventure. First, by setting up the situation, then by introducing it and, finally, by helping the players play through it. The “regular” players have fun by roleplaying their characters and trying to figure out how to accomplish the adventure “goal,” while the gamemaster has fun setting up and running the situations and interactions…and, of course, torturing the player characters. (Page 15 of 224)

Paranoia XP – Core book (Mongoose Publishing, 2004)

A fun and friendly player called the Gamemaster (GM) generously describes the story’s setting and events. […] The GM introduces the game session, describes the setting, and plays the roles of the nonplayer characters (NPCs) you encounter during the story. When you want your character to do something, describe it to the GM. He determines your success using common sense and the game rules. Often he rolls dice, or asks you to roll instead. Because he interprets your success or failure in each action, he thereby determines your success or failure in the whole game. (Page 14 of 256)

Pendragon – Core book, 4th Edition (Chaosium, 1993)

The gamemaster describes the world and events within it to the players. He controls the nonplayer characters.

The gamemaster in a roleplaying game directs the flow of the game while the players control the actions of the characters. As the gamemaster describes what is going on, where they are, and other details of the plot, the players choose actions for their characters, thus cooperating with him in creating the adventure.

The gamemaster oversees the imaginary world, describing it in detail and directing its course. […] When they have questions or need help, players turn to the gamemaster for answers. Likewise, the gamemaster must ask for opinions from the players to make it an acceptable game. (Page 5 of 351)

Primetime Adventures – Core book (Dog-eared Designs, 2004)

During an episode, the producer’s main job is to provide antagonism for the protagonists, in the form of crises, moral dilemmas and occasionally a plain old villain. The producer also has to multitask, feeding individual storylines, incorporating the wishes of players, and playing the part of many supporting characters. (Page 14 of 106)

Prince Valiant – Core book (Chaosium, 1989)

Being the Storyteller is much more work than being a regular player. […] Having control of a story in which your friends play the major roles can be a very interesting and rewarding experience.

The Storyteller has control over everything in the game except the actions of the Adventurers. His job is something like being a referee at a sports event. The referee may or may not be a popular, but he has a certain amount of power over the players. The players must accept this heirarchical situation with grace and politeness, deferring to the Storyteller even when they disagree with him. Remember that everyone can be a Storyteller in the Advanced Game. (Page 7 of 128)

Reich Star – Core book (Creative Encounters, 1990)

It is the Gamemaster (GM) who creates a plot, situation, supporting characters and then acts as a referee. […] In this way, a role-playing game is much like “living” a movie, with the Game-master being writer, director, and supporting cast; and each player is an actor playing the starring role. (Page 6 of 248)

RingworldExplorer Book (Chaosium, 1984)

The gamemaster, the person who moderates the evolving story, prepares challenges for the explorers. He or she maneuvers all the elements of setting and non-player-characters, and interprets the game rules. (Page 2 of 60)

Runequest – Core book (Chaosium, 1978)

The player creates one or more characters, known as Adventurers, and plays them in various scenarios designed by a Referee. The Adventurer has the use of combat, magic, and other skills, and treasure. The Referee has the use of assorted monsters, traps, and his own wicked imagination to keep the Adventurer from his goal within the rules of the game. (Page 3 of 120.)

Serenity Roleplaying Game – Core book (Margaret Weis Publishing, 2005)

One player needs to take charge of the game, and take on extra responsibilities. That’s the Game Master. The GM creates the basic outline of the story that the crew will follow and plays the part of all the NPCs — all those people the crew meets during their adventures. The GM is the players’ window into the ‘Verse. The GM tells the players what they see and hear (and smell and taste and feel). But the GM needs to remember that the crew are the stars of this tale. The players have to make their own choices in the story — meaning they’ll get themselves into trouble all by their lonesomes! The GM has to think on his feet and adjust the story when the unexpected happens (and it will happen!).

Another role the GM plays is that of arbiter. The GM will be the only person who knows all the facts in the game. As there will probably be some disagreements, the GM settles any arguments over the game rules or questions about character creation or how the story develops. Final decisions rest with the GM, but he should remember that his chief job is to help everyone have fun. Fair play is a part of that notion. After all, with power and authority come responsibility. (If you’re a GM, you’d much rather be like Mal than an Alliance stooge, right?) The GM needs to be fair, while still keeping things fun for everyone. (Page 5 of 223.)

The Shadow of Yesterday – Core book, 0.9 Edition (Anvilwerks, 2004)

These players describe what their characters do while one particular player, known in this text as the Story Guide, describes their surroundings and the other characters (often known as non-player characters or NPCs) that they meet. (Page 5 of 38)

Shadowrun – Core book, 1st Edition (FASA, 1989)

The gamemaster has many functions, including creating adventures, roleplaying NPCs, and mediating rules and other formalities of play. (Page 152 of of 214)

Shadowrun – Core book, 3rd Edition (FASA, 1998) (Also the same in 2nd and 4th Edition.)

The gamemaster controls the story. He or she keeps track of what is supposed to happen when, describes events as they occur so that the players (as characters) can react to them, keeps track of other characters (referred to as non-player characters), and resolves attempts to take action using the game system. (Page 10 of 336)

Silver Age Sentinels – Core book, 1st Edition (Guardians of Order, 2002)

As a GM, your contribution will be much greater than that of any one player. You must establish the setting, villains, conflicts, and plot of the adventure, as well as all of the other non-player characters your gaming group will meet in the end. […] Should you assume the role of GM, you must possess creativity, sound judgment, and the ability to improvise in unexpected situations. Game Mastering takes extra time and effort, but the reward of watching the players revel in the game setting and plot you have created makes it all worthwhile. (Page 17 of 336)

Sorcerer – Core book (Adept Press, 2001)

The hope is that playing Sorcerer should generate a good story, specifically one that you and the players are proud of. If you, the GM, don’t have a dramatic narrative goal, why play? (Page 16 of 141)

Space 1889 – Core book (GDW, 1989)

RPG rules are not meant to limit the referee, but rather to free him from having to decide how to resolve every routine event in the game. By freeing him from that task, the rules allow him to make his most important contribution to the game–his imagination.

It is the referee’s imagination that turns the cold, printed words of the rules into a rich, vibrant world, full of colorful characters and thrilling adventure. To make this world come alive for your players, you will have to do four things. The referee must describe the world, play the non-player characters, resolve critical events, and guarantee adventure. (Page 34 of 216)

Stargate SG-1 – Core book (Alderac Entertainment Group, 2003)

The preparation of those obstacles is the purveyance of the Gamemaster (GM), who controls the action and coordinates of the remainder of the gaming universe. If the character are the heroes, then the GM is the supporting cast, as well as the narrator and arbiter of all the rules. He develops the adventures that the characters will go through, planning the mission parameters and the things the characters need to do in order to succeed. As play unfolds, he describes the environment in which the characters find themselves, coordinates plot developments and other twists, and portrays any non-player characters (NPCs) who the players encounter — from the friendly natives to hostile Goa’uld to General Hammond back at the SGC. (Page 6 of 488)

Star TrekPlayer’s Guide (Decipher, 2002)

The Narrator acts out the supporting cast roles, playing the parts of everyone else — the guest star, the villain, and the red-shirted security man who dies in the first act. She becomes the director, the set designer, and the producer; she decides what this week’s episode will be about and adjudicates the rules so everybody knows what they can do to keep the Romulans at bay or the deflector shields up. The Narrator designs individual episodes, Star Trek adventures all your own. (Page 7 of 256)

Star Trek: The Role Playing GameStar Fleet Officer’s Manual (FASA, 1983)

…he moderates the game, keeping in mind and reinforcing the limits and rules of the game. Called the gamemaster, this player judges the effects of the player characters’ actions and determines what the response to those actions will be. He plays all the ‘bit parts,’ the bystanders, villains, and other characters who are not central to the action but who interact with the players’ characters in some way. […] He is responsible for making the game run smoothly so that all have a good time. He guides the action so that the players will succeed — but only after making a number of important decisions and only if they work hard and play their roles well. (Page 4 of 40)

Star Wars – Core book (West End Games, 1987)

The gamemaster, or “GM,” runs the game. When a player wants his or her character to do something, the gamemaster decides what happens, using the rules as a guide. […] He also acts as a “director,” describing the universe in which the characters live to the players. He takes the roles of non-player characters, or “NPCs,” people who live in the Star Wars universe but are not controlled by the players. […] But most important, the gamemaster creates an adventure for his players — a story for their characters to experience, complete with supporting cast, an interesting plot, and rewards for success. (Page 5 of 121)

Star Wars – Core book, 1st Edition (Wizards of the Coast, 2000)

The Gamemaster is the director and special effects designer, deciding what the story is about and taking on the roles of all the other characters — the villains, the extras, the special guest stars. The Gamemaster also keeps track of the rules, interprets the outcome of actions, and describes what happens. (Page 6 of 318)

Tales from the Floating Vagabond – Core book (Avalon Hill, 1991)

This is the Guy in Control, the Head Honcho, the Big Cheese, the Boss, He knows what’s going on in the game world, and lets the Players know, piece by piece, as they find things out. He also dreams up all the little nasties to toss at the Players (Oops! Sorry, Patrons) to make life difficult for them. (Page 5 of 96)

Talislanta – Core book, 4th Edition (Shootingiron Design, 2001)

The Gamemaster plays a vital role in the Talislanta game, serving as a combination narrator, moderator, and role-player. (Page 7 of 502)

Teenage Mutant Ninja Turtles & Other Strangeness – Core book, Revised (Palladium Books, 1988)

The game master (GM) is another player (a real person!) who controls all the characters in the game except the different player’s [sic] characters. (Page 6 of 109)

Toon – Core book, Deluxe Edition (Steve Jackson Games, 1991)

One person, the Animator, runs the game. The Animator tells the players what sort of cartoon they’re in, who (or what) lives there, and what happens. The Animator picks the adventure from the Short Subjects and Feature Films in this book. Experienced Animators can write their own adventures! (Page 5 of 205)

TravellerBook 0 (Game Designers’ Workshop, 1981)

Most games require an umpire of some sort (also called the referee, the judge the dungeon master, ref, ghod [sic], or some other title depending upon circumstances), whose job is to administer the imaginary world in which the players pretend to he gunslingers or swordsmen or whatever and to adjudicate the inevitable conflicts between the players and their environment. In many games the umpire is also the architect of the imaginary world the players explore, creating every aspect of it in as much detail as the players require. […] A referee must keep track of all things that various characters do, determine if and how these actions change the background, decide if and how these changes will affect the characters, note the passage of game time (from a character’s point of view, months may pass in a single evening’s adventure), and adjudicate conflicts between the characters run by the players (called player-characters) and the characters run by the referee (called non-player characters or NPCs). (Page5-7 of 48)

Traveller (Marc Miller’s) – Core book (Imperium Games, 1996)

Management of the game is performed by a special player known as the referee. While the other players each concentrate upon portraying their specific character, the referee portrays all of the places they go and creatures they meet. Like the director of a movie, the referee judges what can and cannot be accomplished in a particular scene. Like the umpire of a sports event, he decides how the game rules apply to the particular situation, and makes rulings based on the spirit of those rules when the action strays outside those boundaries. And like the host of a party, he makes sure that all of the players are involved in the fun and have a good time. (Page 11 of 192)

Traveller20 – Core book (RPG Realms, 2002)

No definition provided. (448 pages)

Tunnels and Trolls – Core book, v5 (Flying Buffalo, 1979)

Someone must create (dig) and stock a dungeon with monsters, magic, and treasure. The person who does that has godlike powers over his or her own dungeons, but is expected to be fair to the other players. The Game Master, or GM (also referred to from time to time as the Dungeon Master, or DM) may not play as a character inside his or her own dungeon. (Pages are not numbered.)

Unknown Armies – Core book, 2nd Edition (Atlas Games, 2002)

Traditionally, the role of Game Master has involved providing a place and time to meet, offering drinks (usually caffeinated in order to heighten player tension and attention), and the occasional salty snack. Plus providing a story, complete with clever puzzles, gripping thrills, and unearthly danger, of course. (Page 275 of 336)

Vampire: The Masquerade – Core book, 1st Edition (White Wolf Publishing, 1992)

The Storyteller describes what happens as a result of what the players see and do, and must decide if the characters succeed or fail, suffer or prosper, live or die. […] The Storyteller’s primary duty is to make sure the other players have a good time. […] As the Storyteller, you are in charge of interpreting and enforcing the rules, yet you are also an entertainer — you must struggle to balance your two roles. (Page 23 of 270)

Villains and Vigilantes – Core book, Revised (Fantasy Games Unlimited, 1982)

His purpose in a role-playing game is to provide those factor that cannot be taken care of by simple die rolls or pages upon pages of rules; that is, variety. It is the GM’s imagination alone which makes a role-playing game enjoyable for the players. (Page 44 of 47)

Warhammer Fantasy Roleplay – Core book (Games Workshop, 1986)

To decide what the players can or cannot do, whether they succeed or whether they fail in any action, there is the gamesmaster (GM). The GM controls the world in which the players’ characters live; he is the final arbiter whose word cannot be disobeyed. […] The GM will use these rules to present a balanced setting in which the fictional characters can adventure. He will make the adventure seem real. But the rules are only guidelines, and when the GM feels he has to change them, he will. (Page 9 of 366)

Warhammer Fantasy Roleplay – Core book (Black Industries, 2005)

The GM is the referee and the lead storyteller, the person in charge of running the game. The GM presents the stories and situations, describes the Warhammer World and its denizens, and adjudicates the rules. The GM is the most important member of your group, so choose wisely. The GM ought to be fair-minded, well spoken, and imaginative. An eye for detail is also helpful. (Page 9 of 256)

The World of Darkness – Core book (White Wolf Publishing, 2004)

This chapter is aimed at the Storyteller alone, the single player most responsible for forming the shape and scope of the story. Players fill in valuable details, and can take the game in interesting directions, but the Storyteller, like a film director, ultimately decides what parts of the collaborative script are made a part of the story. (Page 189 of 223)

The World of Synnibar – Core book, 2nd Edition (Wonderworld Press, 1993)

As Fate is the unseen controller of all destinies in the Centiverse, his or her control is absolute and all decisions are final. […] During the game, as Fate, you may use any reference material within this book. Other players may not unless they have your permission… […] Fate has absolute control during the game regarding rolls and interpretation of the rules. Fate may not, however, deviate from the rules as they are written, for if he or she does and the players find out, then the adventure can be declared null, and the characters must be restored to their original condition… (Page 332 of 477)

Conclusions Based on the Original 30+ Definitions

Having a simple, concise definition of the GM’s role is an essential part of any RPG. It gives new players somewhere to start, and experienced players (who are new to that game) an idea of what the GM does differently in that particular game. Running Primetime Adventures, for instance, isn’t the same as running Star Trek — and their respective definitions do a good job of making that clear.

In looking at this list, there are a number of things that jump out at me. In no particular order:

• Boy, have we come a long way in the past 20 years! I expected this list to show that pretty well, but actually seeing it is a completely different experience.

• There is no “perfect” definition of the GM’s role — but there are plenty of lousy ones. Warhammer Fantasy Roleplay is the worst offender: “he is the final arbiter whose word cannot be disobeyed.” Give me a break.

• A lot of these definitions, especially the older ones, don’t make being the GM sound like fun. Words and phrases that turn me off include “moderator,” “referee,” “the rest of the people involved” and “formalities of play,” among others. If it doesn’t sound like fun, why would anyone want to do it?

• Some definitions improved between editions. Shadowrun, for example, goes from having a pretty useless definition (1st Edition) to having a serviceable one (3rd Edition). Call of Cthulhu shows similar improvement.

• Others, unfortunately, actually got worse over time. I much prefer Vampire: The Masquerade’s definition to the one in World of Darkness, despite the 12-year gap between the two.

It’s unbelievable that a massive tome like Hero System (5th Edition) can’t squeeze a definition of GMing into its 370+ pages. (Update: Actually, I just missed it — sorry about that, Hero! It has a definition, just not a very good one.) Ditto AD&D (2nd Edition), which provides the best example of a non-definition-definition on the list. No wonder it was hard to learn how to play AD&D well!

• The same isn’t really true of kill puppies for satan and Macho Women With Guns (although the latter has a definition, it’s almost completely useless). They’re not designed to be good “first games” in any way, and both are humorous in nature — I don’t expect much in the way of hand-holding, in other words.

• Putting something this important at (or near) the end of a core book is a big no-no. Why should someone who is new to the hobby, or new to that game, have to wade through the whole book to find out something so crucial to the game? Hero System (5th Edition), World of Darkness and Burning Wheel, I’m looking at you.

• My vote for best definitions overall, in order: Burning Wheel (most useful information in the least amount of space — a great balance), Primetime Adventures (clearest, most intuitive definition), Star Trek (incorporates examples, sounds like a lot of fun) and Vampire: The Masquerade (includes an crucial element: “The Storyteller’s primary duty is to make sure the other players have a good time”).

What do you make of this list? What jumps out at you, good or bad — and what do you think makes up a great definition of the GM’s role?

Edit: Also, Travis Casey supplied the definition of “Game Master” from Design Patterns of Successful Role-Playing Games (draft) in his comment below (thanks, Travis!). How does this broad-based, inclusive definition stack up to the others? Is it useful?

Want to Contribute?

As I mentioned up top, this list comes from the books on my shelf — and I’d love to have your help in adding to it. I’m most interested in adding games that fit one or both of these criteria:

  • Doesn’t appear on the list at all.
  • An edition of the same game appears on the list, but the description of game mastering has changed significantly between editions.

To have a game added to the list, you’ll need to make sure you provide the following: full name of the game, source, publisher, edition (if applicable), year of publication, the page number you found the definition on and how many pages are in the book. Sometimes, it may not be obvious what to excerpt — use your best judgment, and pick the most concise section of text if more than one seems to be applicable.

It’s also worth mentioning that I may shorten excerpts as needed. The goal is to quote enough text for comparison purposes (and stay within “fair use”), not to reproduce big chunks of game text.

My thanks to everyone who has already contributed — and thank you in advance for your help!