Faced with the almost inescapable conclusion that it had been selling lemons, Nike shifted into make-lemonade mode. Jeff Pisciotta became head of a top-secret and seemingly impossible project: finding a way to make a buck off a naked foot.

When it comes to mentors, you can't beat survival.

Extreme heroism springs from something that no scientific theory can fully explain; it's an illogical impulse that flies in the face of biology, psychology, actuarial statistics, and basic common sense.

We've created an unnatural form of running. It's not just the shoes, but we run on artificial surfaces - straight ahead, hard and steady - instead of speeding up and slowing down, reacting to the terrain with changes of pace and rhythm.

He was onto something. Something huge. It wasn't just how to run; it was how to live, the essence of who we are as a species and what we're meant to be.

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.

If you don't have answers to your problems after a four-hour run, you ain't getting them.