Jean--Francois Lyotard was one of the most influential European thinkers in recent decades. He was a leading participant in debates about post--modernism and the decline of Marxism, and he made important contributions to ethics, aesthetics and political philosophy. In this authoritative introduction, Williams tracks the development of Lyotarda s thought from his early writings on the libidinal economy to his more recent work on the post--modern condition. Williams argues that despite the wide--ranging character of Lyotarda s writings, they are animated by a long--standing concern to develop a new theory of political action. Lyotarda s productive use of avant--garde art and the aesthetics of the sublime are interpreted within this context. In the final chapters some of the main criticisms that have been levelled at Lyotarda s work are outlined and assessed. A challenging but also accessible book, it will be welcomed by students and researchers in continental philosophy, literary theory and the humanities generally.