The Internet References section, updated, extended, with the links live and clickable. Epicurus, Freud, James, Lucretius, Pirsig and Thoreau online; religious statistics, the Bible and the Pali Canon; etc etc etc.
So far, nobody has reported a serious error. But eagle-eyed reader Joanne K-Z found 20 or so typos, and if you'd like to correct them in your copy, here is the errata sheet as a 1-page PDF file.
"Dostoevsky Didn't Say It: Exploring a widely propagated misattribution" (also published through the Internet Infidels). This is the long version of the discovery condensed in note 13, chapter 2.
"Commandments Five to Eleven: Biblical arguments against public posting of the Ten Commandments" is a more detailed (and less temperate) version of the brief critique of the Decalogue found in Chapter 8.