Short answers, pulled from the story.
The Dungeon Master's Guide is a rulebook for the fantasy role-playing game Dungeons & Dragons that covers the arbitration and administration of a game. It is intended for use by the Dungeon Master, not by other players. It forms one of the three core rulebooks alongside the Player's Handbook and the Monster Manual.
Gary Gygax wrote the original AD&D Dungeon Masters Guide, published by TSR in 1979 as a 232-page hardcover. Mike Carr edited the book and wrote its foreword, and the original cover art was by David C. Sutherland III.
The fifth edition Dungeons & Dragons Dungeon Master's Guide was released in 2014 as the last of the three core rulebooks for that edition. It carried a price of fifty dollars in the United States and was co-led in design by Jeremy Crawford and Mike Mearls.
The fourth edition Dungeon Master's Guide was written by James Wyatt and released on the 6th of June, 2008. It was the first Dungeon Master's Guide not to contain standard magic items, which moved into the Player's Handbook instead. It still contained artifacts, along with rules for building encounters, skill challenges, and monster creation.
The random dungeon generator was a feature of the first edition Dungeon Masters Guide. It let a Dungeon Master roll dice to build a dungeon, complete with passageways, rooms, treasure, and monsters, on the fly. It was dropped from later editions but reappeared in the fifth edition Dungeon Master's Guide.
The second edition AD&D Dungeon Master Guide won an ORIGINS award and a Gamer's Choice award. The fifth edition Dungeon Master's Guide won the 2015 ENnie "Best Supplement" Gold award. It also won the 2015 Origins "Best Role-Playing Game Supplement" and "Fan Favorite" awards.