Nietzsche is often regarded as a paradigmatically anti-theoretical philosopher. Bernard Williams has said that Nietzsche is so far from being a theorist that his text “is booby-trapped not only against recovering theory from it, but, in many cases, against any systematic exegesis that assimilates it to theory.”1 Many would apply this view especially to Nietzsche’s moral philosophy. They would say that even when he is making positive normative claims, as against just criticizing existing morality, his claims have neither the content nor the organization characteristic of moral theory. To me this common view is the opposite of illuminating. I take it as uncontroversial that Nietzsche’s positive moral views fall under the general heading of what today is called perfectionism. They are centred on a conception of the good, which they commend actions for instantiating or promoting, but this conception does not equate the good with anything like pleasure or the satisfaction of desires; instead, it locates the good in objective human excellences that for Nietzsche centre on the concepts of power and strength. Like other moral views, perfectionism can be developed as a systematic theory, and when it is, a series of questions arise about its structure and content. If one reads Nietzsche with these questions in mind, it is striking how often, without formulating them explicitly, he suggests answers to them. And when one combines those answers, the result is a perfectionist theory of a distinctive Nietzschean stripe. Perfectionism has been embraced by, among others, Plato, Aristotle, Aquinas, Leibniz, Hegel, 1 Marx, Bradley, Brentano, Rashdall, and Moore. In my view Nietzsche is the most theoretical of the perfectionists before, say, Brentano, that is, the most likely to recognize and answer theoretical questions. His answers also have a characteristic merit. A standing temptation for moral philosophers, and indeed for philosophers generally, is to avoid difficult theoretical questions by making optimistic factual claims about the world that make competing answers to them compatible...