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.

Writing from both the cutting edge of scientific discovery and the front-lines of elite athletic performance, National Magazine Award-winning science journalist Alex Hutchinson presents a revolutionary account of the dynamic and controversial new science of endurance.

Why does it make sense to Ethiopian runners to get up at three a.m. to run up and down a hill? Who would choose to train on almost impossibly steep and rocky terrain, in hyena territory? And how come Ethiopian men hold six of the top 10 fastest marathon times ever? Michael Crawley spent 15 months in Ethiopia training alongside (and sometimes a fair way behind) runners at all levels of the sport, from night watchmen hoping to change their lives to world-class marathon runners, in order to answer these questions.

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.

Ultramarathons don't leave much room for mistakes. Don't learn the hard way: Get a jump on training for an ultramarathon with Hal Koerner's Field Guide to Ultrarunning, a comprehensive handbook to running 30 to 100 miles and beyond, authored by one of the most experienced and recognized athletes in the sport.