This book has two connected aims. The first is to interpret and evaluate W. D. Ross’s ethics, focusing on the key elements of his moral theory: his introduction of the concept of prima facie duty, his limited pluralism about the right, and his limited pluralism about the good. The second is to articulate a distinctive view intermediate between consequentialism and absolutist deontology, “classical deontology.” According to classical deontology the most fundamental normative principles are principles of prima facie duty, principles which specify general kinds of reasons. Consequentialists are right to think that reasons always derive from goods; and ideal utilitarians are right, contra hedonistic utilitarians, to think that there are a small number of distinct kinds of intrinsic goods. But consequentialists are wrong to think that all reasons have the same weight for all agents. Instead there are a small number of distinct kinds of agent-relative intensifiers: features that increase the importance of certain goods for certain agents. It is argued that classical deontology combines the best elements of the moral theories of Ross and of Sidgwick, and that the best philosophical interpretation of Ross is that he is a classical deontologist.