In April 1957, the English legal philosopher H.L.A. Hart, Professor of Jurisprudence at Oxford, delivered the annual Oliver Wendell Holmes Lecture at Harvard Law School. Hart’s topic was “Positivism and the Separation of Law and Morals,” and he intended his lecture, offered at a “law school deeply influenced by the [legal] realism of Holmes and the sociological jurisprudence of Roscoe Pound,” to be provocative as well as informative. The focus of Hart’s lecture was a core tenet of traditional legal positivism—that there is no necessary connection between law and morality. This was a proposition that would later be defended in detail in Hart’s masterwork, The Concept of Law, published in 1961. Hart’s lecture sought to explain, clarify, and elaborate the positivist account of the relation between law and morality, while at the same time defending legal positivism against the accusation that it was complicitly silent on the evil of oppressive legal regimes.