Genesis 1:1 In the beginning God created the heavens and the earth.
It is remarkable how throughout Genesis we see this contrast between man's failure to appropriate God's overtures of grace and trying to substitute iss own plan, with God ever extending His covenant of salvation through shed blood and reception of faith. Cain and Abel demonstrate this pattern, as well as Noah and the people of his day and the bloodline that would follow from his son Shem and the remainder of humanity. The drama of man's failure versus the top-down reach of God to man in extending grace that saves through faith grounded in the shedding of innocent blood replays repeatedly throughout the Old Testament. Such a pattern served to point the way to what would be the work of Christ on the cross, shedding His blood, and thus grounding salvation that is received by grace through faith.These types of patterns set the stage for what God aimed to do in the choosing of one man and one nation in the second part of the book of Genesis. In short, all of the events of Genesis 1-2 and 3-11 lead up to one family and one man - Abraham.
Genesis 12-50 is about the beginning of heavenly promises, or, the patriarchal narratives consisting of God's dealings with Abraham, Isaac, Jacob and Joseph.
Ultimately, the covenant God made with Abraham would find its ultimate expression and fulfillment in Jesus Christ (Galatians 3-4) and will be finally completed by Him when He returns to restore Israel as a nation at His second coming (Romans 11:25).
Isaac and Jacob stood as the heirs of this promise and Joseph typifies in his life and trials what would be a son, rejected by his brothers for the sake of being a savior of his people. Joseph, interestingly enough, foreshadows Jesus with respect to how Christ would be rejected by His people to be the Savior of His people. The book of Genesis is a marvelous book of the Bible and an awesome beginning to grasping all that God planned to do in unfolding His purposes of creation and redemption through the rest of scripture. Such a volume informs us as to what God wants to do in our lives and what He has achieved through Jesus Christ.