Sling-

You would probably like anything from Richard Dawkins and / or
Carl Sagan. I have a few titles from both of them and they
have some interesting insights on this subject. A few of
the others I have are The End of Faith and the Psycho Bible
but they are tough reading. Those titles you do good to
get through a chapter without your head hurting

Pick some up when you get time

They make for interesting reading.