On evolution, I'd recommend
The Blind Watchmaker and
The Selfish Gene by Dawkins, and Daniel Dennett's
Darwin's Dangerous Idea. Dawkins's books are the best introductions to the subject I've read (and slimmer than
Ancestor's Tale, though I'm looking forward to reading that one).
I'm always surprised that Dennett's book isn't recommended more often. Biology is not his field, so there isn't as much detail in that area as in Dawkins's books. However,
DDD is an astonishingly compelling explanation of the power of natural selection as an algorithm - an explanation of why things are the way they are. He also explores the big philosophical implications of this - the only one to do so this thoroughly, to my knowledge. And he's such a good writer. A real pleasure to read.
I've fewer books to recommend about religion, but Matt Ridley's
The Origins of Virtue: Human Instincts and the Evolution of Cooperation is very fine. I've also had his
Genome on my reading list for a while. I've heard good things about it.
When I first read George Smith's
Atheism: The Case Against God, I used to get a highly amusing range of looks from people who caught sight of the title - from
to
to
to
. On a NYC subway train, a family actually got up and changed seats to move as far away from me as they could.
Now I sometimes read it in public just for fun.
. 