Humans are the only mammals to walk on two, rather than four legs—a locomotion known as bipedalism. But why, and how, exactly, did we take our first steps? And at what cost? Our biology remains better suited to quadruped living: giving birth is more difficult and dangerous; our running speed is much slower than other animals. In FIRST STEPS, paleontologist Jeremy DeSilva explores how unusual and extraordinary our ordinary, everyday walking experience truly is. With forays into developmental psychology labs and ancient fossil sites throughout Asia and Africa, DeSilva investigates the science, culture, and history of walking on two legs. Delving deeply into the story of our past and the new discoveries rewriting the narrative of human evolution, FIRST STEPS examines how upright walking may have laid the foundation for our species’ traits of compassion, empathy, and altruism, and helped us become the dominant species on this planet.