Every culture, in every era, has its adventure myths: The golden hero willing to walk through fire elevates us all beyond our fears and limits. But more often than readily seen, there are darker reasons for dangerous pursuits. Where falls the line between adventure and madness? Geoff Powter, a practicing clinical psychologist, looks into the stories of eleven troubled adventurers, divided into three categories: The Burdened, The Bent, and The Lost.

Polar explorer Robert Falcon Scott has been called a "willing martyr" ready to die for the mystical deliverance of adventure.

Meriwether Lewis, convinced that he had failed to achieve the objectives set by mentor and father figure, Thomas Jefferson, died by his own hand.

Maurice Wilson's plan for climbing Everest included deliberately crashing his plane as high as possible on the mountain.

Jean Batten was a remarkably driven early aviator whose clothes and make-up were always more perfect than her flying technique.

Polar balloonist Solomon Andrée was certain that his rigorous understanding of scientific principles would overcome any challenge posed by nature or equipment failure.

Aleister Crowley, a brilliant mountaineer who founded the Golden Dawn cult, was labeled pathologically, and even fatally, arrogant.

In each of these stories, darkness of some kind—ambition, ego, a thirst for redemption, the need to please others—carried these characters in a perilous direction. In the end, understanding these difficult but utterly human stories helps us comprehend the deepest purpose and allure of adventure, and, ultimately, to more honestly measure ourselves.