Charleston was in ruins. The peninsula was nearly deserted, the fine houses empty, the streets littered with the debris of fighting and the ash of fires that had burned out weeks before. The Southern gentility was long gone, their cause lost. In the weeks after the Civil War ended, it was, some said, "a city of the dead." On a Monday morning that spring, nearly 10,000 former slaves marched onto the grounds of the old Washington Race Course, where wealthy Charleston planters and socialites had gathered in old times. During the final year of the war, the track had been...