We are the biggest sissies in the jungle. Every other animal is stronger than we are - they have fangs, they have claws, they have nimbleness, they have speed. We think Usain Bolt is fast - Usain Bolt can get his ass kicked by a squirrel.

Even Charles Darwin, that human decoder ring of bizarre behavior, found the idea of saving a stranger's life to be a total head-scratcher.

The words of the social critic Eric Hoffer were ringing true: "Every great cause begins as a movement, becomes a business, and turns into a racket."

That was the real secret of the Tarahumara: they'd never forgotten what it felt like to love running. They remembered that running was mankind's first fine art, our original act of inspired creation.

Endurance, after all, is the only reason we even exist. We think of ourselves as nature's deadliest animals, but the truth is, a naked human is the biggest wimp in the wild. We have no fangs, no claws, no strength, and no speed.

One of the most dangerous and best-kept secrets of the medical profession is the epidemic of anesthesiologists who are addicted to their own drugs.

Were designed for persistence hunting, which is a mix of running and walking. Whats built into that kind of running is a sense of pleasure. You are designed and built and perfect for this activity, and it should be enjoyable and fun.