Joseph Raz (; ; born Zaltsman; 21 March 19392 May 2022) was an Israeli legal, moral and political philosopher. He was an advocate of legal positivism and is known for his conception of perfectionist liberalism. Raz spent most of his career as a professor of philosophy of law at the University of Oxford associated with Balliol College and was latterly a part-time professor of law at Columbia University Law School and a part-time professor at King's College London. He received the Tang Prize in Rule of Law in 2018. Life and career Joseph Zaltsman was born on 21 March 1939 in Haifa (then in Mandatory Palestine) to Sonya and Shmuel Zaltsman. He graduated in 1963 from the Hebrew University of Jerusalem with a Magister Juris, summa cum laude. Also in 1963, he changed his surname to Raz. Later, with funds provided by the Hebrew University, Raz pursued a doctorate at the University of Oxford under the supervision of H. L. A. Hart. Raz had met Hart earlier at a conference in Israel, impressing him by pointing out a flaw in his reasoning that had previously eluded him; Hart encouraged him to go to Oxford for further study. Raz studied at Balliol College and completed his Doctor of Philosophy in 1967. After completing his PhD, Raz returned to Israel to teach at the Hebrew University as a lecturer in the faculty of law and department of philosophy. In 1971, he was given tenure and promoted to senior lecturer. In 1972, he returned to Balliol as a fellow and tutor in law, becoming a professor of philosophy of law, Oxford University, from 1985 to 2006, and then a research professor from 2006 to 2009. In 2002, he also became a professor at Columbia Law School in New York and starting in 2011 was a research professor of law at King's College London. Raz died on 2 May 2022 at Charing Cross Hospital in his sleep. The Oxford Law Faculty called him "one of the last remaining giants of jurisprudence and philosophy". Philosophical work Political philosophy Raz's first book, The Concept of a Legal System, was based on his doctoral thesis. A later book, The Morality of Freedom, won two prizes: the 1987 W. J. M. Mackenzie Book Prize from the Political Studies Association of the United Kingdom, awarded to the best book in political science each calendar year; and the 1988 Elaine