'My legacy will be like cash which is distributed to many heirs, each transforming his portion into a profit that conforms to his nature: this profit will no longer reveal its derivation from my legacy' - Georg Simmel (1918). These prophetic words, written shortly before Simmel's death in 1918, have held true to the present day. His immense cultural capital was distributed to many heirs, but after his death there remained little trace of where it came from. This work resuscitates Simmel's reputation among his contemporaries as 'the philosopher of the avant-garde' by revealing the cultural origins of his sociological thought. Naturalism, socialism, and Nietzsche contributed to the formulation of a social theory that galvanised Simmel's reputation as the greatest social critic of Wilhelmine Germany. Ralph Leck examines Simmel's impact upon significant movements of the period: radical feminism, literary Expressionism, the homosexual rights movement, the antiwar activist movement, and Western Marxism. As a result of Leck's research, Simmel emerges for the first time as a key figure in the intellectual history of the European counterculture. Simmel's wide-ranging social theories-dealing with such themes as feminism, alienation, money culture, social hierarchy, and fashion - are still relevant to current debates about gender, sociological, cultural, and political theory.