Those who appreciate Sam Harris' book will also want to look at "Created From Animals - The Moral Implications of Darwinism" by James Rachels; Oxford Univ. Press, 1990; available in paper. I've found this to be an absolutely absorbing book, having read it now numerous times (as I have Harris' book). It's beautifully written, very "accessible" and has a lot to tell us. The chapter titles—after the first one, being a brief biography of Darwin himself—will give you a feeling: How Evolution and Ethics Might be Related, Must a Darwinian be Sceptical About Religion?, How Different are Humans from Other Animals? and Morality without the Idea that Humans are Special. I very strongly recommend it for being on your shelf right next to The End of Faith.
Sadly, Rachels, a philosopher and medical ethicist, died in 2003. But long-live Sam!
(Also sadly, I'm afraid faith in unverifiable propositions will always be with us, the most disastrous of such being, of course, the faith in an afterlife. All others, humankind could put up with but that one is the killer, literally, since it's what allows, "He who dies killing others will live forever in paradise". ...and its corollary, "The more you kill, the sooner you will get there.")