In retrospect, that was really what did it for me. I held on to various forms of wishful thinking for a long time, because it seemed to me that minds and matter were fundamentally separate things, I couldn't see how it could be any other way--though I knew at that point that religious claims tended to be laughable, so I had some kind of vaguely half-assed do-it-yourself wishing-makes-it-so I believed in--and that implied the whole universe of dualism. Somehow I came away from it having relinquished that idea, and it, more than any other one book I'd read by that age, set the course for my intellectual journey.
And indeed, I was reading the twentieth anniversary edition, which even warned me up front: "In a word, GEB is a very personal attempt to say how it is that animate beings can come out of inanimate matter. What is a self, and how can a self come out of stuff that is as selfless as a stone or a puddle?"
(Also, come to think of it, I'd have skipped ahead a long way on the philosophy of uploading if I'd read A Conversation with Einstein's Brain a few years earlier.)
In an Open Thread comment beriukay mentioned that he's reading C.S. Lewis' Mere Christianity. I've been reading it too, for interesting reasons.
In my case it so happened that I started discussing faith with a long-time online friend whose spiritual views I didn't yet know, and he turned out to be a Christian with a high regard for the Bible, who also has an interest in science. As our discussion turned to our readings on spirituality, I acknowledged (I think it was me) that I probably spent more time on books that reinforce my point of view than on books that challenge it, perhaps a case of confirmation bias. (I've been exposed to many poor arguments for Christianity, and dismissed them; but possibly that was largely a function of having started out with that bottom line already written and picking arguments I wouldn't have much trouble refuting.)
In the spirit of experiment we agreed to a "trade" - he would read (thoughtfully and with an open mind) a book of my choosing on reasons to doubt faith, and I'd do the same with a book he chose on Christianity.
So the idea here is to pick a book that's the "best argument from the other side" (as in quote 3 here).
I recommended The God Delusion - I'm not sure if that's the best choice given the above intent, but it's what came to mind on the spot.
Would you make a different choice? If so, what?