Genesis, meaning "beginning," covers the times from the creation (i.e. the beginning of history) to the Israelite sojourn in Egypt. The book falls naturally into two main sections: chapters 1-11 deal with primeval history; chapters 12-50 treat the history of the "fathers" of Israel. The latter section tells the stories of Abraham (chapters 12-25), of Isaac and his twin sons Esau and Jacob (chapters 26-36), and of Jacob's family, the chief member of which was Joseph (chapters 37- 50).
Unlike the stories of primeval history, those of the patriarchs can be read against the background of the history of the Near East in the early part of the second millennium B.C. (2000-1500), as documented from extra-Biblical. The primary purpose of the whole book, however, is to narrate God's dealings with men and, in particular, to interpret Israel's special role in his historical plan. Thus the call of Abraham (12.1-3) is the great turning point. God's creation had been marred by man's persistent wickedness which not even the flood erased. Out of this fallible human material, however, God gradually separated one family line and eventually chose one man, Abraham, promising that he and his people would have a great historical destiny and would be instrumental in bringing divine blessing upon all the dispersed families of mankind.
The book is composed of three main literary traditions (Judean, Ephraimite, and Priestly) and these, in turn, often preserve ancient oral tradition. Thus the voices of many generations unite in the affirmation that the only true God is the God of Abraham, Isaac, and Jacob, whose redemptive purpose, like the rainbow of his promise, spans the course of human history from its remote beginning to its unrealized future.