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 4:10-12
"And he said, What hast thou done? The voice of thy brother’s blood crieth unto me from the ground. And now art thou cursed from the earth, which hath opened her mouth to receive thy brother’s blood from thy hand; when thou tillest the ground, it shall not henceforth yield unto thee her strength; a fugitive and a vagabond shalt thou be in the earth"