H. L. A. Hart

Herbert Lionel Adolphus Hart was a British legal philosopher. One of the most influential legal theorists of the 20th century, he was instrumental in the development of the theory of legal positivism, which was popularised by his book The Concept of Law. Hart's contributions focused on the nature of law, the relationship between law and morality, and the analysis of legal rules and systems, introducing concepts such as the "rule of recognition" that have shaped modern legal thought.