In the beginning...
The word genesis means 'beginning' - an appropriate title for the book of the same name. Not only is it the beginning of the Bible, being the first book, it also tells of the beginning of the world and how it was created by God. The Book of Genesis also describes how sin came into the world and how God exercises His judgement, but also His mercy, on mankind.
Genesis 9:14-16
"And it shall come to pass, when I bring a cloud over the earth, that the bow shall be seen in the cloud: and I will remember my covenant, which is between me and you and every living creature of all flesh; and the waters shall no more become a flood to destroy all flesh. And the bow shall be in the cloud; and I will look upon it, that I may remember the everlasting covenant between God and every living creature of all flesh that is upon the earth"