Who is H. L. A. Hart from The Concept of Law and what is their importance?

Herbert Lionel Adolphus Hart (1907-1992) was a professor of legal and moral philosophy at Oxford in the middle of the twentieth century. He wrote a number of important philosophical works, but the profession widely regards The Concept of Law as his finest contribution to philosophy and law. Hart went to Cheltenham College and New College for his education and became a Barrister (a British lawyer), practicing law between 1932 and 1940. During the Second World War, Hart worked for British intelligence and after the war took up a teaching position in philosophy at Oxford. In 1952 he was made Professor of Jurisprudence at Oxford and retired in 1969. Hart was also a major influence on a number of late twentieth century philosophers including Brian Barry, John Finnis, Kent Greeawalt, Joseph Raz, Ronald Dworkin and John Rawls.