Revised damage reduction for easier play with advancement and individualization of monsters. Contain improved layout and statistics but isnt for everybody.

This is the most revised. Monsters have been largely redesigned to integrate with the PH and add specialization to run as characters. Damage reduction has been overhauled to take weapon type into account rather than just magic power. Skills and feats have been added to allow improvement of monsters, making them your own. Combat tactics and ecology info have been added as well.

The new version is a definite improvement over previous works. Like the DMG, it is not necessary for every player to own, but I would recommend that every gaming group have at least a few of them available.