Short answers, pulled from the story.
The Dungeons and Dragons Rules Cyclopedia is a 304-page hardback rulebook published by TSR, Inc. in 1991. It compiled and revised the rules from the Basic, Expert, Companion, and Master Rules boxed sets of the basic edition of Dungeons and Dragons into a single reference volume. Its product designation was TSR 1071.
The Rules Cyclopedia was designed by Aaron Allston. Reviewer Rick Swan praised Allston's prose style in Dragon magazine issue 184, writing that the book was a joy to read thanks to Allston's "breezy style."
The Rules Cyclopedia allows players to develop and play characters from level 1 through level 36. This range was drawn from the compiled Basic, Expert, Companion, and Master Rules sets.
The Rules Cyclopedia contains an overview of two campaign settings: the Known World, also called Mystara, and the Hollow World.
Rick Swan reviewed it in Dragon magazine issue 184 in August 1992, calling it a "stunningly comprehensive volume" and "a must for serious fans." Shannon Appelcline described it as "a nice compilation that was appreciated by the fans."
The Rules Cyclopedia includes the druid, first introduced in the Companion ruleset, and the mystic, introduced in the Master ruleset. The mystic is similar to the monk class found in Advanced Dungeons and Dragons.