This book develops and defends a version of utilitarianism, including expected-utility theory, as a normative model of decision making. The defense, based on the idea of utility as achievement of goals, considers the endorsement of a norm as a decision and asks what reasons we have to endorse norms for decision making. The reasons derive from our pre-existing goals, so any norm we endorse must not fly in the face of these goals, although it must not be selfishly biased, either. This approach is further clarified by drawing distinctions between decisions for the self, for a single other person, for several others, and for the self and others. The book discusses the implications of this argument for the psychological study of decision making, the act--omission distinction, moral education, decision analysis, risk analysis, and other questions of public policy. The final chapter sketches a prescriptive approach to group decision making.