Bernd Heinrich is a professor of biology, holder of a world record and several US records in marathon races, a physiologist, and a specialist in thermoregulation and exercise. In this book, he reflects on the sport of running as a natural scientist, recounts his participation in the 100K race that launched his ultramarathon career, and draws parallels between humans and the rest of the animal kingdom. Endurance, intelligence, the will to win - this is the main motto of ultramarathon runners, which can lead to the highest achievements. “I argue that our ability and passion for running is our ancient heritage, the preserved skills of endurance predators. Although they may be camouflaged in modern members of our species, our bodies are still ready to run and/or chase imaginary antelopes. We don't always see them in reality, but our imagination encourages us to look far beyond the horizon. The book serves as a reminder that the key to understanding our evolutionary adaptations—the ones that make us unique—lies in observing other animals and the lessons we learn from them.” (Bernd Heinrich)