When Chris McDougall stumbled across the story of Churchill's 'dirty tricksters', a motley crew of English poets and academics who helped resist the Nazi invasion of Crete, he knew he was on the track of something special.

To beat the odds, the tricksters-starving, aging, outnumbered-tapped into an ancient style of fitness: the lost art of heroism.

They listened to their instincts, replaced calories with stored bodily fat and used their fascia, the network of tissue which criss-crosses the body, to catapult themselves to superhuman strength and endurance. Soon McDougall was in the middle of a modern fitness revolution taking place everywhere from Parisian parkour routes to state-of-the-art laboratories, and based on the know-how of Shanghai street-fighters and Wild West gunslingers.

Just as Born to Run got runners off the treadmill and into nature, Natural Born Heroes will inspire casual athletes to dump the gym membership for cross-training, mud runs and free-running.