Book that begins in Egypt (6)
I believe the answer is:
exodus
'book that begins in egypt' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for exodus that I've seen before include "sequel to first one" , "Biblical book -- group escape from a hostile environment" , "Mass leaving" , "Outgoing" , "Great departure of people like Jews from Egypt" .)