Below the ocean's surface there are forms of life that could not seem more foreign to our own: sea sponges, soft corals, and flower-like worms, whose rooted bodies and intricate geometry are more reminiscent of plant life than anything recognizably animal. As fellow members of the animal kingdom, though, these Metazoa can teach us about the evolutionary origins of not only our bodies, but also our minds. Having uncovered the wonder of the octopus in Other Minds, Peter Godfrey-Smith follows the evolutionary chain in both directions here, trying to answer one of the most important philosophical questions: what is the origin of consciousness?