David Clark is a formerly obese alcoholic and fast food junkie who found a new life in running. Now, 13 years after his transformation, he shares his inspiring story of taking running to the extreme edge of his physical and spiritual breaking points. Having run more than a hundred races, including the Leadville 100-Mile Trail Run and the Hardrock 100, David has achieved unimaginable success in the ultramarathon world, considering his humble start.

After a decade-long addiction to crack cocaine and alcohol, Charlie Engle hit bottom with a near-fatal six-day binge that ended in a hail of bullets. As Engle got sober, he turned to running, which became his lifeline, his pastime, and his salvation. He began with marathons, and when marathons weren't far enough he began to take on ultramarathons, races that went for 35, 50, and sometimes hundreds of miles, traveling to some of the most unforgiving places on earth to race.

Scott Jurek is one of the world's best known and most beloved ultrarunners. Renowned for his remarkable endurance and speed, accomplished on a vegan diet, he's finished first in nearly all of ultrarunning's elite events over the course of his career. But after two decades of racing, training, speaking, and touring, Jurek felt an urgent need to discover something new about himself. He embarked on a wholly unique challenge, one that would force him to grow as a person and as an athlete: breaking the speed record for the Appalachian Trail.

Isolated by Mexico's deadly Copper Canyons, the blissful Tarahumara Indians have honed the ability to run hundreds of miles without rest or injury. In a riveting narrative, award-winning journalist and often-injured runner Christopher McDougall sets out to discover their secrets. In the process, he takes his readers from science labs at Harvard to the sun-baked valleys and freezing peaks across North America, where ever-growing numbers of ultra-runners are pushing their bodies to the limit.

Aside from her rock star looks, Catra Corbett is a standout in the running world on her accomplishments alone. And, unbelievably, she's also a former meth addict. After two years of addiction, Catra is busted while selling, and a night in jail is enough to set her straight. She gives up drugs and moves back home with her mother, abandoning her friends, her boyfriend, and the lifestyle that she came to depend on. Her only clean friend pushes her to train for a 10K with him, and surprisingly, she likes it and decides to run her first marathon after that.