Herbert Lionel Adolphus Hart (18 July 1907 – 19 December 1992) was a British legal philosopher, and a major figure in political and legal philosophy. He was Professor of Jurisprudence at Oxford University and the Principal of Brasenose College, Oxford. His most famous work is The Concept of Law (1961; 3rd edition, 2012). It has been argued that Hart had redefined the domain of jurisprudence and moreover established it as a philosophical inquiry of the "nature" or "concept" of law. He is considered one of the world's foremost legal philosophers in the twentieth century, alongside Hans Kelsen.