The Book of Enoch is a non-canonical Jewish work attributed to Enoch, the great-grandfather of Noah. The book is thought to date to about 300 BC and includes a detailed account of the fall of the angels in its section, the Book of the Watchers.
The Watchers were a class of angels described in the non-canonical Book of Enoch. The term usually refers to the rebellious angels who married human women, begot offspring (called Nephilim) and were kicked out of Heaven. Read articles about the Watchers below.