From the back cover:

Monsters Abound in the Dread Realm

The world of Ravenloft holds terrors that stalk the night and prowl the realms even in daylight. From the doomed creatures that subsist on the blood of the living to canny shapeshifters and hideous constructs, the monsters of Ravenloft lurk in every corner, seeking hapless adventurers as their prey. Only the bravest dare hunt them.

A Bestiary of Terror

This core sourcebook overhauls the original Denizens of Darkness and adds a host of new monsters native to Ravenloft. It provides essential information including abilities, ecology and tactics of the many creatures of the Dread Realm, and everything is updated to be compatible with the Dungeons & Dragons 3rd Edition revised Players Handbook. Hardcover.

Ravenloft books are published under license with Wizards of the Coast and are 100% compatible with version 3.5 rules and the d20 System.