The Book of Enoch was an apocryphal book of the Bible.
Removed from the Bible in the 4th century supposedly because it was out of date, it and the Book of Noah were suppressed for having what was considered dangerous knowledge, expanding on the account in the Book of Genesis of the mating of angels and humans.
It was brought from Ethiopia to Europe in 1773, but not translated into English until 1821. The book was believed to contain information about the origins of the Mal'akh. (PROSE: The Book of the War)