Book excerpt: A New York Times bestselling author takes readers inside the Ironman triathlon. As he did so masterfully in his New York Times bestseller, The Gatekeepers, Jacques Steinberg creates a compelling portrait of people obsessed with reaching a life-defining goal. In this instance, the target is an Ironman triathlon-a 2.4-mile open-water swim followed by a 112-mile bike ride, then finally a 26-mile marathon run, all of which must be completed in no more than seventeen hours. Steinberg focuses not on the professionals who live off the prize money and sponsorships but on a handful of triathletes who regard the sport as a hobby. Vividly capturing the grueling preparation, the suspense of completing each event of the triathlon, and the spectacular feats of human endurance, Steinberg plumbs the physical and emotional toll as well as the psychological payoff on the participants of the Ford Ironman Arizona 2009. His You Are an Ironman is both a riveting sports narrative and a fascinating, behind-the scenes study of what makes these athletes keep going..