Dungeon Master's Guide (3.0 Edition)

Blurb

The Dungeon Master's Guide is a book of rules for the fantasy 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. The original Dungeon Master's Guide was published in 1979, and gave Dungeon Masters everything they needed to run a D&D game campaign.
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 Monster Manual are collectively referred to as the "core rules" of the Dungeons & Dragons game. Both the Dungeon Master's Guide and the Player's Handbook give advice, tips, and suggestions for various styles of play.
While all players, including the Dungeon Master, are expected to have at their disposal 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.