The book argues that running is a fundamental evolutionary human skill developed for endurance rather than speed. McDougall shows that many common running injuries are not caused by running itself but by how people run: inefficient mechanics, excessive cushioning, overtraining, and disconnection from bodily feedback. By examining indigenous running cultures and elite endurance athletes, the author highlights the importance of natural biomechanics, lightness, cadence, and movement economy. Effective running relies less on complex technology and more on simplicity, body awareness, patience, and enjoyment. Running well means running sustainably, efficiently, and with pleasure.