The word "genesis" has reference to origins. Genesis is the book of origins, the book of beginnings. We have the beginning of the material universe, the beginning of the human race, the beginning of human sin, the beginning of divine redemption, the beginning of the nations of the earth, the beginning of the Hebrew nation, the beginning of the life of faith and consecration.
I believe Genesis was written by Moses. Most conservative scholars agree.
The most important verse is certainly Genesis 3:15:
And I will put enmity Between you and the woman, And between your seed and her seed; He shall bruise you on the head, And you shall bruise him on the heel."
The purpose of Genesis is not to give a detailed history of the human race, or the history of science. It's primary purpose is to tell us about Abraham and certain of his descendants. Abraham is the one whose descendant, Christ, would bless all nations of the earth (Gen. 22:17-18; Gal. 3:15-29). Redemption is the basic theme.
17 indeed I will greatly bless you, and I will greatly multiply your seed as the stars of the heavens and as the sand which is on the seashore; and your seed shall possess the gate of their enemies.
18 "In your seed all the nations of the earth shall be blessed, because you have obeyed My voice."
Now the promises were spoken to Abraham and to his seed. He does not say, "And to seeds," as referring to many, but rather to one, "And to your seed," that is, Christ.