Is there some kind of Demonic book that rivals the Bible? What is it called?

A long time ago, when i was in the service, this guy from New Orleans, told me he worshipped the devil. He stated that there is alot of devil worshippers. He started saying something in some kind of language that i never heard before. He said it was devil talk. He knew the translation and everything. It came to mind, because I just got finished watching "Fallen". He had a book similar to what was in the movie. Does anyone know about this so called Devil's book?