In May 1999, Elizabeth Mitchell and her boy-friend, Chuck Fulgham, rented a car and drove on a whim from New York City to Louisville for the Kentucky Derby. They knew nothing about horse racing, but they were ripe for good fortune: Fulgham, who'd been a Peace Corps volunteer near Chernobyl, had acute myelogenous leukemia and was just beginning to taste health again after his second month of chemotherapy. The night before the race, Mitchell dreamed about an art exhibition at Brown, where a man kept asking her if the paintings had "charisma." The next morning she learned that a chestnut colt named Charismatic was running for the Roses. Charismatic won the race, at odds of 31-1, and Fulgham and Mitchell were among the ecstatic winners.

What Mitchell didn't know at first was that the three-year-old colt had performed so poorly the previous year that his trainer, D. Wayne Lukas, and his owners had twice put him in claiming races, hoping someone would take the fat, lazy animal off their hands. Lukas was running Charismatic in the Derby out of a stubborn conviction that the horse had potential - if only he were ridden right.

The jockey who would ride him right was also climbing up from rock bottom. Chris Antley had become notorious for his bravado, aggression, and drug and alcohol abuse. He'd won the Derby in 1992 but was so strung out he didn't remember crossing the wire. Then, at age twenty-six, Antley experienced a jockey's nightmare: a growth spurt. He grew an inch and a half and gained fifteen pounds over the next six years. "Antley began running fifteen to twenty miles a day," Mitchell writes. "He climbed on a stationary bicycle and rode another twenty-six miles. He tried to flip [vomit] as often as he could. He starved himself and even took the Lasix that the trainers used on the horses as a diuretic. He sat in the 130-degree hotbox in the jockeys' room for hours." At age thirty-two Antley quit. His weight ballooned to 147, and he retired to his father's house in South Carolina to watch TV.

Then, just as abruptly, Antley began seeing a psychiatrist (he'd earlier been diagnosed bipolar), dieted, and ran so much the locals dubbed him Forrest Gump. By January 1999 he was down to 116 pounds. In mid-April, Lukas asked him to ride in the Derby. "Charismatic is a gift," Antley said.

Mitchell, the former executive editor of George and author of W: Revenge of the Bush Dynasty, meticulously researched the web of stories that merged in Charismatic's 1999 win. Her book also explores the violence of the track, and the history of both racing and gambling. The story she tells is tragic. After winning the Derby and the Preakness, Charismatic fumbled at the Belmont, losing the third jewel of the Triple Crown. Antley - who had once walked away from an injured horse, allowing the panicked animal to destroy himself - jumped off and shouldered Charismatic's injured leg until help arrived. Charismatic survived, but he never raced again.

Then, on December 2, Antley was found dead in his home in California. The early police reports indicated a homicide, but the coroner blamed drugs. Antley's friends believed he was killed by someone in the racing business. Mitchell's love affair turned out tragically, too: Chuck Fulgham died of cancer.

Some readers will fault Mitchell for weaving the two stories together, and horse people will sniff out errors of both fact and understanding. What Mitchell does know is how it feels to win and to lose, and her book resounds with the yearning that draws us back to the track - and to love - even after losing all.