"SUM" is a dazzling exploration of funny and unexpected afterlives that have never been considered-each presented as a vignette that offers us a stunning lens through which to see ourselves here and now. In one afterlife you may find that God is the size of a microbe and is unaware of your existence. In another, your creators are a species of dim-witted creatures who built us to figure out what they could not. In a different version of the afterlife you work as a background character in other people's dreams. Or you may find that God is a married couple struggling with discontent, or that the afterlife contains only those people whom you remember, or that the hereafter includes the thousands of previous gods who no longer attract followers. In some afterlives you are split into your different ages; in some you are forced to live with annoying versions of yourself that represent what you could have been; in others you are re-created from your credit card records and Internet history. David Eagleman proposes many versions of our purpose here; we are mobile robots for cosmic mapmakers, we are reunions for a scattered confederacy of atoms, we are experimental subjects for gods trying to understand what makes couples stick together. These wonderfully imagined tale-at once funny, wistful, and unsettling-are rooted in science and romance and awe at our mysterious existence: a mixture of death, hope, computers, immortality, love, biology, and desire that exposes radiant new facets of our humanity.