Bill Mounce has an article about translating γένεσις in Matt 1.1: γένεσις and the title of Matthew’s gospel (Monday with Mounce 194). He offer three suggestions, following Don Carson, for the expression βίβλος γενέσεως:
- “record of the genealogy” (pointing to Matt 1:1-17)
- “record of the origins” (which would be the title to the prologue, 1:1–2:23)
- “record of the history” (which would be a title to the whole book)
I myself am partial to a fourth suggestion by Dale Allison: “Book of the Genesis,” which points to the first book of scripture.