The Gray Book

From the Introduction:

I started out by trying to compile all the rules presented in the Dungeons & Dragons® rules and supplements into one cohesive whole. Based on Bruce Mohler’s prior work, I aimed to present this book as if it were the book that Eric Holmes had written all along, before severe editing pared down the rules to the 48 pages that exist today. The largest difference between Bruce’s work, this work, and the original rules is the absence of both the rather poor Greg Bell art, and references/dependencies to Chainmail®. A major goal was to complete what Bruce had started, but as work progressed, the book was steadily becoming less a "Dungeons & Dragons compilation" and more of an "Advanced Dungeons & Dragons Light".