The track was an unfamiliar size, so I didn't have context for the times they announced after each lap. I wondered if there had been an error when the time for the first mile was called—5:25, by far my fastest ever. I finished in fifth place in a class-record time of 10 minutes and 48 seconds. The football star read about it in the school paper and congratulated me. I had practiced reasonably hard, but you don't set records because of two months of doing the same workouts as everyone else. Clearly, my genes had played a role.

My father, meanwhile, had been given the most valuable mulligan one can get. A year after his diagnosis, he'd entered into a study of HIV-positive men, only to be informed that his initial diagnosis had been incorrect; he was HIV-free. Years later, he would tell me that the initial death sentence was what had enabled him to live. Until he was forced to confront what dying would actually mean, his sexual choices had been reckless. His days of competitive running, though, were behind him. By the time I picked up the sport in high school, he was in his early fifties, and his back, his knees, and his constantly blackened toenails wouldn't let him go for more than a few miles. He was a man who liked to do things all in or not at all. He put his running shoes away.

Boys improve more or less linearly at running until they turn into men. If you train steadily, your hormones work in concert with your muscles. Add increasing self-confidence to the mix and you get a positive feedback loop: Speed leads to confidence leads to speed. By my senior year, I was a New England prep school track champion and headed off to Stanford and the Pac-10. But the pattern of improvement only holds if you stay healthy. The summer before I started college, I increased my weekly running miles from about 35 to about 70. My legs got stronger, but then they frayed. I showed up on campus with a stress fracture in my shin expecting to run cross-country races. A few months later, just as I was gingerly trying to train again, a doctor told me I had mononucleosis. The next summer I swam in polluted water and came down with hepatitis. I knew something was wrong when, on a run in the woods of Northeast Harbor, Maine, I stopped by a bed of moss and saw my pee had turned black.

Quitting the team was hard, but not running was easy. I convinced myself that the focus required by Division I sports would have narrowed the aperture of my college imagination. With no track practice, I had time for a million other things, including playing acoustic guitar. And so the fall after graduation, I moved to a farm in New Hampshire to concentrate on music.

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At some point that summer, though, sitting by a granite stone wall and feeling lonely, I decided to try racing again. I was reaching inside myself because there was less going on outside. The realization that I wasn't good enough at guitar to make it my life was hitting me. There was no distraction of friends and parties and classes. I needed something to do. What I came up with was taking my father's goal and making it my own: run a three-hour marathon. I even asked him to do it with me, but he demurred. My training consisted of running a few days a week and strolling through sugar maples on the others. I was clueless. I entered a marathon in Providence and ended up struggling fitfully across the line in 3:18.

For the next decade, I trained episodically and entered marathons now and then while beginning a journalism career that had me moving every few years—from New Hampshire to West Africa to Washington, DC, to New Haven. I dropped out of one marathon at mile 23 because my knee hurt. My father, who loved my new hobby, was left waiting at the finish. I missed another when, driving with my father down to southern Virginia, we got a flat tire the morning of the race. The fastest I ran was a 3:07 in Maryland the year of the sniper. As I hit my late twenties, the three-hour goal seemed impossible.