Description Enoch was the Great Grandfather of Noah.
We first learn of Enoch.
The Book of Enoch chapter 67:1 "And after that my great grandfather Enoch gave me all the secrets in the Book and in the parables which had been given to him, and he put them together for me in the words of the Book of the parables."This makes it possible for the Book to have survived the flood as its not too hard to accept that Noah would have taken his Great Grandfathers writings with him onto the ark.
Description Enoch was the Great Grandfather of Noah