The Krivbeknih

 is a book added to Fallout 3 in the Point Lookout add-on.

Said to possess a dark power, it used to be in the possession of the Blackhall family but was lost long ago. It can be destroyed by pressing it against the obelisk in the Dunwich Building, an artifact of similar evil.

Related quest: The Dark Heart of Blackhall
Obadiah Blackhall wants you to retrieve this book from the Ritual Site in Point Lookout whereas Marcella wants it destroyed.

Behind the Scenes
The Krivbeknih is a reference to the many esoteric and arcane tomes featured in the Cthulhu Mythos, such as the Necronomicon, Book of Eibon, Pnakotic Manuscripts, Etc. These artifacts play a similiar role in the mythos, often being used by evil men for sinister purposes.