This thesis is a biographical study of P.R. Stephensen (1901-1965), writer, publisher and political activist. It focuses on the 1920s and 30s when he was the manager of four publishing companies, in London and Sydney, and also the author of much political and literary journalism as well as of books and translations. Stephensen possessed a romantic as well as sardonic view of himself, and one of the challenges presented by his life is to resolve or balance the many intellectual and ideological contradictions of which it was composed. He has remained something of a puzzle for historians, and this thesis seeks to trace his rebellious personality, and indeed some of his more extreme ideas, not only back to their origins in the First World War, but also back to the peculiar heritage of his Danish-French-Swiss Australian roots. His literary career and interests were extensive and varied, but they can not be separated from his almost anarchic political spirit. Along with "Heroic Vitalists" such as Carlyle, Nietzsche, Wagner and D.H. Lawrence, Stephensen was a mixture of anarchy, rebellion and authoritarianism, and like them he inherited the "attitude of the literary man as critic of the age and devil's advocate". (Eric Bentley, A Century of Hero-Worship, 1957 ed., p. 246.) This thesis presents Stephensen in the milieu of the 1920s to the 1950s, and traces his relationship with such figures as Jack Lindsay, D.H. Lawrence, Aleister Crowley, Liam O'Flaherty, Miles Franklin, Norman Lindsay, Xavier Herbert, Frank Clune and Ian Mudie. His central role as an Australian nationalist is also discussed and assessed, especially in relation to his important polemic The Foundations of Culture in Australia (1936), and his involvement with the Australia-First Movement.