I still don't have all five of the books I'm going to read for this challenge, but I think I'm going to leave the last possibility open to whatever book I discover. Here's my list:
Beware of God - Shalom Auslander
The Wholeness of a broken heart - Katie Singer
The World to Come - Dara Horn or In the Image by the same author
Suite Francaise by Irene Nemirovsky
The list can change at any time.