From publisher blurb:
Since the release of the first bestiary, the first monster book, there have been those who asked - can I play something exotic, can I play a monster instead of a regular character?
In this release of the Monster Classes series, you have the opportunity to play as an undead, to become a deathless ghost or a ghoul. As an undead creature, your experience playing in the Pathfinder Roleplaying Game is sure to be unique and filled with unexpected situations.
This book includes two monster classes - the deathless ghost and the ghoul, along with associated feats necessary to build interesting undead characters, that at the same time are true to the concept presented in the Bestiary. Enjoy!