I read the 'Old Testament' all the way through when I was about 13 and was horrified. A few months afterwards I read 'The Origin Of Species', hallucinating very mildly because I was in bed with flu at the time. Despite that, or because of that, it all made perfect sense.
A Slip of the Keyboard: Collected Nonfiction (ed. Anchor, 2014) - ISBN: 9780385538336