Universal Mysteries by Ahmed Hulusi. When I saw this book in the Amazon Kindle store I had to find out why it had created such a fuss. It got so many reader reviews. At the time, the translation was pretty weak, but now it has been updated. Caution: mind-expanding concepts within.
Aiden and I love this book. It focuses on how people of all different kinds of religions view God and the similarities they have. Leaves them with the message that we are all connected and God is all of us and is everything. Excellent for getting a good dialogue going with your kiddo.