More than eighty years after his death, Nietzsche's writings and his career remain disquieting, disturbing, obscure. His most famous views-the will to power, the eternal recurrence, the bermensch, the master morality-often seem incomprehensible or, worse, repugnant. Yet he remains a thinker of singular importance, a great opponent of Hegel and Kant, and the source of much that is powerful in figures as diverse as Wittgenstein, Derrida, Heidegger,...