Genesis is the first book of the Bible, and is mostly a book of history. It was written by Moses at command of God as one of the five Books of the Law, or Pentateuch. This book contains most of the events described in the Books of the Law.
Chapters 1-11 tell about the creation and beginning of the world. The second part (Chapters 12-50) talks about the beginning of a family (Abraham’s line) in which later would bring us someone who would redeem us. The second part of Genesis records the beginnings of God’s redemption of mankind, through a covenant He made with the three patriarchs of the Christian faith: Abraham, Isaac, and Jacob.