Within the English-speaking world, H.L.A. Hart (1907–1992) is regarded as the twentieth century's foremost legal philosopher. He revived the moribund discipline of jurisprudence, reorientating it so that the qualities associated with analytical philosophy in the second half of the twentieth century2 were applied to the investigation of the most fundamental concepts of law and to major public issues, notably, the complex relation between law and morality. As a colleague, teacher, mentor, and author, he exercised a profound influence, an influence that extended to the ‘real world’ and ‘real issues’. From the late 1950s onwards, he championed a new humaneness in punishment, speaking and writing for a right to abortion and against the death penalty and the prosecution of people because of their sexual preferences. His exploration of the balance between the modern welfare state and individual liberty - in particular, the legitimate use of state power to impose standards of private morality -produced an eloquent and highly influential manifesto for modern political liberalism. As Tony Honore, his close colleague at Oxford, put it,‘He was the most widely read British legal philosopher of the twentieth century and his work will continue to be a focus of discussion.