Robin Harvie was a fairly regular runner. He ran his first marathon following a guess. Then he found that though he couldn’t run rapidly, he could run prolonged distances—very prolonged. A informal passion turned into a a hundred and twenty-miles-a-week obsession, and a education route along the River Thames morphed into a promise to himself that he would tackle the oldest and toughest footrace on earth: the Spartathlon from Athens to Sparta. This race, a recreation of Pheidippides’s renowned journey, is 150 miles prolonged, crosses two mountain ranges, and is the toughest race on the ultradistance runner’s calendar. It is not at all regular.

Harvie’s experience—from the mundanity of daily education routes to the severe assessments of the desert’s scorching heat and the darkest hours of the night—reveals the profoundly intoxicating encounter of operating, and the methods in which each and every mile taken is equally a phase additional into the unidentified and a tempo deeper into the self.