Book of Vile Darkness is an optional supplemental sourcebook for the 3rd edition of the Dungeons & Dragons role-playing game. The book was written by Monte Cook and published by Wizards of the Coast in October 2002. Described as a "detailed look at the nature of evil," it was the first Dungeons & Dragons book labelled for mature audiences. The second was the "good" companion volume Book of Exalted Deeds. Another Book of Vile Darkness was published for the 4th edition of D&D in 2011.