Among endurance runners, there are those who have run very long distances, and then there are those who have run very long distances for a very long time. Ed Ayres exemplifies the latter; having run in over 600 races across fifty-five years, he is arguably the most experienced American distance runner still competing today. A book no one else could have written, The Longest Race is his urgent exploration of the connection between individual endurance and a sustainable society. The Longest Race begins at the starting line of the 2001 JFK 50 Mile—the nation’s oldest and largest ultramarathon and, like other such races, an epic test of human limits and aspiration. At age sixty, his sights set on breaking the age-division record, Ayres embarks on a course over the rocky ridge of the Appalachian Trail, along the headwind-buffeted towpath of the Potomac River, and past momentous Civil War sites such as Harpers Ferry and Antietam. But even as Ayres focuses on concerns familiar to every endurance runner—starting strong and setting the right pace, the art of breathing, overcoming fatigue, mindfulness for the course ahead—he finds himself as preoccupied with the future of our planet as with the finish line of this 50-mile race. A veteran journalist and environmental editor who harbors deep anxiety about our longterm prospects, Ayres helps us to understand how the skills and mindset necessary to complete an ultramarathon are also essential for grappling anew with the imperative to endure—not only as individuals, but as a society—and not just for 50 miles, but in the longest race we are all called upon to run.