From the back of the Book:
The Cure for the Common Game
Throw off your chains! Too long have your role-playing games been held in the bonds of substandard gamemasters, bound in needlessly complicated rule sets, and enslaved by players who will avoid doing anything unless it counts toward leveling up! It is time to take a stand!
Learn from the masters the ancient secrets of how to:
* Become a certified XDM and impress dates (Do-it-yourself secret initiation rites included.)
* Design epic adventures that tell stories.
* Perform magical feats to amaze your players, and even make them disappear!
* Employ actual combustion (yes, "fire," and yes, it's dangerous) to enhance your games!
* Hijack any game as a player, and deal with any player revolution as an XDM!
From the Website
God does not play dice with the universe. We do.
XDM: X-Treme Dungeon Mastery is a hard-bound, 160-page illustrated tome whose toothy, monochromatic pages will add more color to your game than any other supplement you might buy. Its principles work with every role-playing system known to man, and it includes the fully-playable XD20 system which allows the true Extreme Dungeon Master to render any of those other systems obsolete... or at least completely superfluous.