In One and Five Ideas eminent critic, historian, and former member of the Art & Language collective Terry Smith explores the artistic, philosophical, political, and geographical dimensions of Conceptual Art and conceptualism. These four essays and a conversation with Mary Kelly-published between 1974 and 2012-contain Smith's most essential work on Conceptual Art and his argument that conceptualism was key to the historical transition from modern to contemporary art. Nothing less than a distinctive theory of Conceptual and contemporary art, One and Five Ideas showcases the critical voice of one of the major art theorists of our time.