In "Why We Run, " biologist, award-winning nature writer, and ultramarathoner Bernd Heinrich explores a new perspective on human evolution by examining the phenomenon of ultraendurance and makes surprising discoveries about the physical, spiritual -- and primal -- drive to win. At once lyrical and scientific, "Why We Run" shows Heinrich's signature blend of biology, anthropology, psychology, and philosophy, infused with his passion to discover how and why we can achieve superhuman abilities.