As one of the most complex, charismatic and controversial figures of our times, Robert Kennedy occupies a remarkable and paradoxical place in the American imagination. On the right he has been idolized by Rudy Giuliani and memorialized by Attorney General John Ashcroft, who renamed the Justice Department after him. On the left, his admirers say he represented the last hope of revitalizing the liberal tradition. But who was Robert Kennedy? To acclaimed...