Flann O'Brien's The Third Policeman, completed in 1940, was initially rejected by his publishers for being 'too fantastic', and only appeared posthumously in 1967. Since then O'Brien has achieved cult status, although critical appraisal of his work has focused almost exclusively on his first novel, At Swim Two Birds (1939). By 1940 O'Brien was confronted with two towering traditions: the jaded legacy of Yeats's Celtic Twilight and the problematic complexities of Joyce's modernism. With The Third Policeman O'Brien forges a powerful synthesis between these two traditions, and the paraliterary path he chooses marks the historical transition from modernism to post-modernism. This groundbreaking study, first published in 1995 and now substantially revised, reconfigures O'Brien as a highly subversive writer within a rich and fertile literary landscape: indisputably Irish yet distinctly post-modern. It identifies The Third Policeman as a subversive intellectual satire, in the cutting-edge tradition of Swift and Sterne, and situates it as one of the earliest - and most exciting - examples of post-modernist fiction.