M&M Companion: Additional Rules & New Options for Revised Mazes & Minotaurs is the "fourth book in the trilogy". While the previous three books satirizing the 3-volume format of AD&D contained the core rules, this volume is entirely composed of a collection of optional rules, divided into sections on characters, divine agents, combat, religion, miscellaney, and an appendix with a mass combat system.
Notes on This Edition
The Silver Jubilee Edition is a minor revision of the original version, incorporating rules adjustments, clarifications, and additions, with a new cover. The 2012 version of the
Companion has the most changes of any of four core books, with 7 pages of new material from the
Minotaur magazine. 50 pages, free.