Susan Jacoby: Freethinkers: A History of American Secularism

Excellent overview of the prominent role that freethinkers (atheists, agnostics, and deists) played in America's past, including the founding of our country, the abolition of slavery, and giving women the vote. (*****)

Sam Harris: The End of Faith: Religion, Terror, and the Future of Reason

One of the most frightening books I've ever read. Among numerous other topics, Harris argues that it is almost inevitable that atomic weapons will fall into the hands of religious radicals -- if not terrorist, then perhaps a nation with religious radicals in charge. (****)

Richard Dawkins: The God Delusion

Highly recommended. Despite what you might have heard, Richard Dawkins does not spew venom in this book. Flames do not shoot out when you open it, nor does bile drip from the pages. Far from being an hysterical, rabid diatribe against religion, it is a quite measured, logical explanation of the evidence against God and why religion should not be treated with such reverence. (*****)

Daniel C. Dennett: Breaking the Spell: Religion as a Natural Phenomenon

I highly recommend this book for anyone who is about to embark on studying religion and atheism. Why do people enjoy music? Why do we like to socialize? Why do we sometimes become violent? Science has attempted to answer each of these questions. Dennett proposes that science attempt to answer another: Why are people religious? Even if one of the religions is true, that still means that billions of people believe religions that are not true. Why? What is it about our evolutionary past that makes us willing to believe? (*****)

Jared Diamond: Guns, Germs and Steel: The Fates of Human Societies

Why wasn't Europe invaded by ships carrying gun-wielding Native Americans or Africans, rather than the other way around? This is an excellent explanation of why some societies became quite advanced, while others remained primitive. (*****)

Terry Pratchett, Ian Stewart, Jack S. Cohen: The Science of Discworld

You'll have to visit Amazon UK to locate this one. This book explains science concepts by comparing them to the decidedly different physical laws of the Discworld series. (****)