Some thoughts on How We Believe: Science, Skepticism, and the Search for God, by Michael Shermer.
"Unusually useful... May foreshadow a new spirit of amity and mutual inquiry."
The above statement from The Washington Post Book World, which is quoted on the front cover of this book, sums up this book quite well. Shermer is one of the best known unbelievers writing today, and his work has an accessibility absent from a lot of similar books. Maybe it's because he was an Evangelical at one time, and so has personal, happy experiences with religion; or maybe it's because he has a Masters degree in Psychology and a PhD in History (of science), and so spends his days trying to understand people and ideas. Whatever the case, he is one of the more balanced authors out there writing on the science/religion type of stuff.
Shermer attempts to follow in the footsteps of some scientists before him in writing for a popular audience. Therein lies both the strength and weaknesses of his books, including this one. Shermer is not afraid to explore a lot of territory that your average Joe is not normally exposed to, such as the studies which show that some people are "wired" in their brain to be more religious than others. The problem is that, as he is writing for a popular audience, he rarely does more than skim the surface of any one topic. He touches on a very intriquing topic, speculates briefly on what meaning it could have as to "how we believe," and then moves on.
I remember reading a review (I think on Amazon) which said that this book was basically just a compilation of what people (including Shermer himself) have already said in other books. That's a fair enough statement. This book is an overview of the current thought as to how we believe, and not anywhere near an exhaustive treatment. Still, if your interested in the subject, and don't really want to delve into the more complex Dennett, Dawkins, etc., it might be worth picking up.