The first part of the book examines English origins of substantive due process, with reference to the Magna Carta and English law limitations on private monopolism. The second part covers substantive due process in the New World, the focus being on expropriation by public conversion, monopoly by public grant, and monopoly by private contract. The third part considers substantive due process in the United States as inherited from England. In discussing the residual legacy of substantive due process, the fourth and final part considers the relation between substantive due process and expropriation, public monopoly, and private monopoly. An index of cases is included.