That's the title of a book I haven't gotten hold of yet.
But I already know when Jesus became God.
I know it because of the Wednesday Bible study we have at Trinity.
We talked about the council of Nicea--where the Nicene Creed came into being and the Doctrine of the Trinity became part of the belief of the church.
Until 325 a.d. some Christians believed Jesus was 'chosen' by God to be the Savior. But the Council made clear that Jesus was 'begotten' by God, created from God's own being.
That's when Jesus became God.
If you haven't looked into the Council try it out on line. Wikipedia has a good recounting of it.
Very interesting stuff to dig around in.