Cover of the 4th printing of the Advanced Dungeons & Dragons Dungeon Masters Guide

The Dungeon Master's Guide ("DMG" or "DM's Guide"; in earlier editions, the Dungeon Masters Guide) is a book of rules for the seminal role-playing game Dungeons & Dragons. The Dungeon Master's Guide contains rules concerning the arbitration and administration of a game, and is intended for use primarily or only by the game's Dungeon Master. It is intended as a companion book to the Player's Handbook, which contains all of the basic rules of gameplay, and the Monster Manual, which is a reference book giving statistics and characteristics to various animals and monsters. The Player's Handbook, Dungeon Master's Guide and the Monster Manual are collectively referred to as the "core rules" of the Dungeons & Dragons game. While all players, including the Dungeon Master, are expected to have to be able to refer to a copy of the Player's Handbook, only the Dungeon Master is expected to refer to the Dungeon Master's Guide or Monster Manual during gameplay.

Like other volumes of Dungeons & Dragons handbooks, the Dungeon Master's Guide has gone through several versions through the years. Fans of the original Advanced Dungeons & Dragons game often deride the Second Edition Dungeon Master's Guide for its paucity and lack of flavor.

The Dungeon Master's Guide contains scores of tables and charts for figuring damage and resolving encounters in a typical adventure, tables and rules for creating characters, and lists of the various abilities of the different classes of characters. More obscure and esoteric aspects of the game can be found in supplementary publications, such as issues of Dragon Magazine or rulebooks like the Psionics Handbook or Deities & Demigods.

One of the most useful features of the guide is the Random Dungeon Generator. The generator allowed, by the rolling of dice, to generate a dungeon adventure "on the fly." A dungeon complete with passageways, rooms, treasure, monsters and other encounters could easily and randomly be constructed as the player progressed. Best of all, it could be used with several people or a single player. This was a useful tool to easily beef up new characters and to allow players to play the game when others weren't available to play.

For many players, the three core rulebooks were referred to so often that some players wore out one or more copies of each book over the years. This led to the development of the Dungeon Master's Screen: two heavy-duty boards with the most oft-used tables printed on them for easy reference. The screen could be stood on-end to shield players' eyes from notes, rolls and other adventure bookkeeping. The Advanced Dungeons & Dragons Second Edition screen came packaged with a brief adventure; later editions of that screen, and screens produced for later editions, have instead included character sheets and general reference booklets.

External link

• Detailed information on the Dungeon Master's Guide and differences between printings