David Eagleman's Sum is the most surprising, delightful, and thought-provoking book I've read in a long, long time.
In its far-flung flights of imagination, it reminds me of Einstein's Dreams, by Alan Lightman (who is quoted on the back cover). Instead of concepts about time, though, the subject of Sum is the afterlife.
What I like most, I think, is that many of the forty possible afterlives Eagleman dreams up turn out to be lessons in unintended consequences. For us and for God.