Read the book.
A few times actually, and many others like it.
Loved it and confirmed my position that the idea of God is just that, an idea.
I think that is all well established for the philosophical and historically minded.
The 'idea of God' is now very well documented and anyone still believing in an extraterestial sitting in the clouds throwing lightening bolts is deluded.
Next step is, why God and religion in the first place?
Some recent stuff I have been reading is in regard to the evolutionary adaption of the human to accept the possibility of 'god' and higher spirits.
Why has the human gone down the religious path?