Reference, Dungeons & Dragons 

The third of three core rulebooks for the 4th Edition Dungeons & Dragons® Roleplaying Game.The Dungeons & Dragons Roleplaying Game has defined the medieval fantasy genre and the tabletop RPG industry for more than 30 years. In the D&D game, players create characters that band together to explore dungeons, slay monsters, and find treasure. The 4th Edition D&D rules offer the best possible play experience by presenting exciting character options, an elegant and robust rules system, and handy storytelling tools for the Dungeon Master.The Dungeon Master's Guide gives the Dungeon Master helpful tools to build exciting encounters, adventures, and campaigns for the 4th Edition Dungeons & Dragons Roleplaying Game, as well as advice for running great game sessions, ready-to-use traps and non-player characters, and more. In addition, it presents a fully detailed town that can serve as a starting point for any D&D game. - from Amzon