CHRISTOPHER McDOUGALL covered wars in Rwanda and Angola as a foreign correspondent for the Associated Press before writing his best-selling book Born to Run. His fascination with the limits of human potential led to his next works, Running with Sherman and Natural Born Heroes, and his Outside magazine web series, "Art of the Hero."

ERIC ORTON's experiences with the Tarahumara and his study of running, human performance, strength, and conditioning have led him to the cutting edge of the sport and made him a go-to for athletes everywhere. The author of The Cool Impossible and former fitness director for the University of Colorado Health Sciences Center, Orton personally trains athletes from recreational racers to elite ultramarathoners. He lives in Jackson Hole, Wyoming.