"The Book of Giants" is an expansive narrative of the biblical story of the birth of 'giants' in Genesis 6.1-4. In this story, the giants came into being when the Watcher 'sons of God' (who, per the story's corroborative Jubilees account 4:15; 5:6, God originally dispatched to earth for the purpose of instructing and nurturing humanity "in proper ritual and ethical conduct," "to do what is just and upright upon the earth") were seduced by and had sexual intercourse with mortal women, who then birthed a hybrid race of giants. These Watchers ("grigori") and giants ("nephilim") engaged in destructive and grossly immoral actions which devastated humanity, including the revealing of heaven's holy "secrets" or "mysteries to their wives and children" and to mankind generally.