Exodus 1:1. the book is called Shemoth in Hebrew and to the Jews the most important book as that is their story and it defines the Torah with them being the center of it. Genesis left off with the 12 sons in Egypt. from the Adam Clarke commentary and my words on exodus 1.
These are the names - Though this book is a continuation or the book of Genesis, with which probably it was in former times conjoined, Moses thought it necessary to introduce it with an account of the names and number of the family of Jacob when they came to Egypt, to show that though they were then very few, yet in a short time, under the especial blessing of God, they had multiplied exceedingly; and thus the promise to Abraham had been literally fulfilled. See the notes on Genesis 46 (note).