Combining the adrenaline high of extreme sports with the startling facts of physiological reality, Stark narrates a series of outdoor adventure stories in which thrill can cross the line into mortal peril. Each death or brush with death is at once a suspense story, a cautionary tale, and a medical thriller. Will they survive, or will they succumb? Stark describes in unforgettable detail exactly what goes through the mind of a cross-country skier as his body temperature plummets - apathy at 91 degrees, stupor at 90. He puts us inside the body of a doomed kayaker tumbling helplessly underwater for two minutes, five minutes, 10 minutes. He conjures up the physiology of a snowboarder frantically trying not to panic as he consumes the tiny pocket of air trapped around his face under thousands of pounds of snow.

These are among the dire situations that Stark transforms into harrowing accounts of how our bodies react to trauma, how reflexes and instinct compel us to fight back, and how, why, and when we let go of our will to live.