Subtitled "A Guide to Critical Hits, Fumbles, and Magical Mishaps" Compatible with any RPG system that uses critical hits. From the back cover: "This book contains over 60 tables tailored to every need: simple, quick crits and fumbles decided by the roll of a d6; more sophisticated tables requiring a d20 or multiple dice, and our grand charts which have hundreds of possibilities. There are charts that are weapon specific and others that are opponent specific (mounted opponents, winged opponents, etc.). One of the spell fumble tables is even specific to spell level and school of magic!"