I cannot recommend enough 'A History of God' by Karen Armstrong. Whilst I am not monotheistically religious (and possibly not religious at all, depending on your definition), this book has proved invaluable in increasing my understanding of monotheistic religion and in answering my questions as to why people believe what they believe and defend what they defend in their religion. Armstrong manages to write about this issue in an exceptionally balanced and non-judgemental way, which is both illuminating and refreshing.
So, get over to Amazon.com and widen your meme set: whether you see it as a
gateway to common understanding (recommended approach) or an exercise in
'know-your-enemy' psychology, it won't be a wasted read, and should do much
to increase the depth of discussion about religion on this list, if nothing else.