Over at Evolvefish.com they have a section on humanist books.
One book that intrigues me is the World’s 16 crucified saviors before Christ. . I cannot find it through the library system and really don’t have extra cash to blow on something I may or may not like. This annoys me to no end.
My problem with anything that is geared towards disputing religion ( or talking about religion in general) is that it usually is dry from scholarly application of, yanno, facts. ( which is why, I suppose, religion is so popular. No facts, just fantastical stories!!)
I can’t offer a recommendation, but if you’d like another list of possible titles, here is what is offered in the Humanism section of the Unitarian Universalist Association bookstore:
While I haven’t read the book mentioned in the OP, I’d be willing to bet that it’s not all that different (at least in terms of premise) than Joseph Campbell’s The Hero With a Thousand Faces or Bible Myths and Their Parallels in Other Religions by T. W. Doane (which you can download for free at that link). Having read both Campbell and Doane, I’ve gotta say Doane’s the better scholar.