These notes are just my opinions based on what the book says and other things that I have read. You may find them surprising, and hopefully interesting, and there are some links to further reading.
How old is the Book of Enoch?
Who were the Fallen Angels?
Who were the Watchers?
Is Yahweh, who appears in the book as "the Lord of the sheep", an extraterrestrial?
Enoch met the Seven Sages
Some interesting science and astronomy found in the book