DragonQuest Rulebook (2nd Edition) (1982)

From the back cover:

The most powerful and comprehensive fantasy role-playing system is now even easier and more fun in the thoroughly revised second edition. The combat system has been streamlined for quicker and more exciting play, and the experience points system has been carefully enhanced to make your characters capable of more dynamic growth. Now presented in this one volume, DragonQuest is truly complete in one book. Although we are continuing a program of fascinating supplemental material, you need nothing more than this book and two decimal dice to play complete and enjoyable games.

A fan microbadge is available