As it now stands, I Enoch appears to consist of the following five major divisions:
(1) The Book of the Watchers (chaps. 1-36);
(2) The Book of the Similitudes (chaps. 37-7l)-,
(3) The Book of Astronomical Writings (chaps. 72-82);
(4) The Book of Dream Visions (chaps. 83-90); and
(5) The Book of the Epistle of Enoch (chaps. 91-107).

Ancient Texts for New Testament Studies: A Guide to the Background Literature (ed. Hendrickson Publishers, 2005)