The Book of Enoch
Composite pseudepigraphic work, sometimes called 1st Enoch (unlike the 2nd -- Slavonic -- Enoch), completely preserved only in Ethiopic (Ge`ez). There are also two extensive fragments of the texts in Greek found in Akhmim in 1886. In addition several hundreds of Aramaic fragments were discovered in Cave IV in Qumran in 1952. This so called Book of Enoch is divisible into five originally separate portions:

Book I

(The Book of Watchers)

Chapters 1 - 36

Introduction; contemplation of the nature; descent of two hundreds angels to Earth - - they took human women for their wives, begot children (giants), led mankind astray but finally were destroyed by God; Enoch's journeys in Heavens, Earth and Underworld.  This may be the most ancient part of the collection. Dated back to the 3rd century B.C.

Book II

(The Book of Parables)

Chapters 37 - 71
Description of the days of the Last Judgment; journey to Heaven; meeting with the Chosen One; uncovering of all heavenly mysteries.  Dating of the book varies from the 1st half of the first century B.C.  to the end of the first century A.D.

Book III

(The Astronomical Book)

Chapters 72 - 82
Description of revolution of heavenly bodies that Uriel the angel revealed to Enoch.  Qumran fragments of this text are dated to the end of the 3rd of the beginning of the 2nd century B.C. Existence of older Hebrew text is possible but unsure.

Book IV

(The Book of Dreams)

Chapters 83 - 90

Vision of destruction of Earth; vision of world history from Adam to the first days of heavenly Kingdom -- cattle, sheep and other animals represent main characters and their features.   Aramaic fragments from Qumran corresponding to this texts are dated to the third quarter of the 2nd century B.C.

Book V

(The Epistle of Enoch)

Chapters 91 - 108

Testament of Enoch; chapter 93:1 - 14 and 91:12 - 17 respectively -- so called Apocalypse of the Ten Weeks describing world history from the beginning the Last Judgment and creation of new heavens.  Dated to the half of the 1st century B.C.  It is not clear when exactly and from which sources the Ethiopic translation was created.  Most probably both Aramaic and Greek versions were used; influence (or even existence) of some Hebrew verbage was discussed but is still unclear.  Also included is a fragment of the Book of Noah, describing the conditions that led Noah's father to question his son's parentage and how the question was answered.
NOTE:  At some point in its history, it is believed that the Book of Giants was replaced by either the Book of Parables or the Astronomical Book.  If you know, please inform me, thanks!!!