A clever little book by a neuroscientist translates lofty concepts of infinity and death into accessible human terms. What happens after we die? Eagleman wonders in each of these brief, evocative segments. Are we consigned to replay a lifetime's worth of accumulated acts, as he suggests in “Sum,” spending six days clipping your nails or six weeks waiting for a green light? Is heaven a bureaucracy, as in “Reins,” where God has lost control of the workload? Will we download our consciousnesses into a computer to live in a virtual world, as suggested in “Great Expectations,” where “God exists after all and has gone through great trouble and expense to construct an afterlife for us”? Or is God actually the size of a bacterium, battling good and evil on the “battlefield of surface proteins,” and thus unaware of humans, who are merely the “nutritional substrate”? Mostly, the author underscores in “Will-'o-the-Wisp,” humans desperately want to matter, and in afterlife search out the “ripples left in our wake.” Eagleman's turned out a well-executed and thought-provoking book.