There are parties, and then there are parties that leave everyone else feeling terribly underdressed. On November 28, 1966, Truman Capote commandeered the Grand Ballroom of the Plaza Hotel and summoned 540 of his nearest and dearest to what would become the Black & White Ball. He called it a little masked ball. New York called it the party of the century, and has been calling it that ever since. Officially, the evening honoured Katharine Graham, the formidable publisher of The Washington Post. Unofficially, it was a small masterpiece of Truman's peculiar genius: an instinct for the social appetite, and the nerve to feed it. The timing was no accident. In Cold Blood had made him famous in a way that even he, a man who had rehearsed for fame since childhood, could scarcely have rehearsed for. He was rich, he was celebrated, and he was, one suspects, a little restless. A man in that condition can write another book, or he can give a party. Truman, being Truman, chose the party and...