We all have ethical beliefs. We may believe, for example, that torture is wrong, that compassion is a virtue, and that it is rational to promote what one values. These beliefs are normative; they concern what we ought or ought not to do, or what is valuable or worthy of our choosing, or what a society must try to guarantee. The problem of normativity is to explain what the normativity of these beliefs comes to. What is it for an ethical claim, an ethical judgment, or an ethical fact to be normative? All of the main problems in metaethics can be traced back to the problem of normativity. They arise in the form they do because ethics is normative.Ethical realists hold that there are ethical facts that are the truth-makers of ethical beliefs -- facts such as the fact that torture is wrong -- facts that are similar in all metaphysically and epistemologically important respects to biological, psychological, and physical ones. Ethical realism faces a variety of objections, but the most important is its purported inability to account for the normativity of the ethical facts that it postulates. Some philosophers think that the normativity objection poses an especially acute challenge to ethical naturalism because of its view that the ethical properties and facts are natural ones. David Copp aims to explain the naturalist's position, why it is important, and why we might find it plausible despite the objections it faces. He argues that, in fact, ethical naturalism is better positioned to answer the normativity objection, and to explain the nature of normativity, than its alternatives.