For nearly two decades, Scott Jurek has been a dominant force—and darling—in the grueling and growing sport of ultrarunning. In 1999, as a complete unknown, he took the lead of the Western States Endurance Run, a 100-mile traverse over the old Gold Rush trails of the California Sierra Nevada. He won that race seven years in a row, setting a course record along the way. Twice he won the Badwater Ultramarathon, a 135-mile “jaunt” through Death Valley. Recently he set an American record of 165.7 miles in 24 hours—6 1/2 marathons in one day. And he was one of the elite runners who traveled to Mexico to run with the Tarahumara Indians, as profiled in the bestseller Born to Run. His accomplishments are nothing short of extraordinary, bu