The Book of Giants
The Book of Giants is thought to have been based on the Book of Enoch, a pseudepigraphical Jewish work from the 3rd century BCE, itself based on an obscure passage from Genesis (6:1-4) concerning Nephilim, which, in the Enoch version, are the offspring of fallen angels; they saw the beauty of the daughters of men, married them, and thus fathered Giants in the land. The book concerns itself with filling in the details about the giants and their offspring that the Book of Enoch is lacking.
In the version of the Book of Giants which was spread by the Manichaean religion, the book became well traveled and exists in Syriac, Greek, Persian, Sogdian, Uyghur, and Arabic, although each version is somewhat distorted, incorporating more local myths. In 1904, German expeditions to Central Asia (Turpan in present northwest China) brought back many fragments of Manichaean holy texts, some of which were identified as belonging to The Book of Giants.
The text relates how some giants, named Ohya, Hahya and Mahway, sons of the fallen angels, have some dreams that foresee the Biblical Deluge. A brief mention of one of these giants, "Ohya", is found in the Babylonian Talmud (Nidah, Ch 9), where it is said "סיחון ועוג אחי הוו דאמר מר סיחון ועוג בני אחיה בר שמחזאי הוו" ("Sihon and Og [from the Book of Numbers] were brothers, as they were the sons of Ohia the son of Samhazai [one of the leaders of the fallen angels in the Book of Enoch]"). The version found at Qumran also describes the sumerian hero Gilgamesh and the monster Humbaba.
Ogias the Giant 
The Gelasian Decree mentions a Latin Book of Ogias the Giant which was identified with the Manichaean Book of Giants, an identification confirmed by evidence among the Parthian fragments of the Manichaen work.
- The Book of Giants, Dead Sea Scrolls
- Summary of the Book of Giants by James R. Davila
- The Book of the Giants, 1943
- Józef T. Milik (with Matthew Black), The Books of Enoch, Aramaic Fragments of Qumran Cave 4, Clarendon, Oxford 1976
- John C Reeves - Jewish Lore in Manichaean Cosmogony: Studies in the "Book of the Giants 1992 p22 "This "Book of Ogias the Giant" was plausibly identified with the Manichaean Book of Giants even before the discovery of confirming evidence among the Parthian fragments of the latter work.85 Here it should be noticed that Ogias engages ..."