Private law is a familiar and pervasive phenomenon. It applies our deepest intuitions about personal responsibility and justice to the property we own and use, to the injuries we inflict or avoid, and to the contracts which we make or break. The Idea of Private Law offers a new way of understanding this phenomenon. Rejecting the functionalism popular among legal scholars, Ernest Weinrib advances the provocative idea that private law is an autonomous and noninstrumental moral practice, with its own structure and rationality. Weinrib draws on Kant and Aristotle to set out a formalist approach to private law that repudiates the identification of law with politics or economics. Weinrib argues that private law is to be understood not as a mechanism for promoting efficiency but as a juridical enterprise in which coherent public reason elaborates the norms implicit in the parties' interaction. The book combines philosophical exposition and legal analysis, and pays special attention to issues of tort law. Private law, Weinrib tells us, embodies a special morality that links the doer and the sufferer of harm. Weinrib elucidates the standpoint internal to this morality, in opposition to functionalists, who view private law as an instrument in the service of external and independently justifiable goals. After establishing the inadequacy of functionalist approaches, Weinrib traces the implications of the formalism he proposes for our ideas of the structure, coherence, and normative grounding of private law. Furthermore, the author shows how this formalism manifests itself in the leading doctrines of private law liability. Finally, he describes the public but nonpolitical role of the courts in articulating the special morality of private law.