Since 1914 Marcel Duchamp has been called all of these. No artist of the twentieth century has aroused more passion and controversy, nor exerted a greater influence on art--the very essence of which Duchamp challenged and redefined as concept rather than product by questioning its traditionally privileged optical nature. At the same time, he never ceased to be engaged, openly or secretly, in provocative and enigmatic activities and works that transformed traditional art-making procedures. This definitive monograph, written with the enthusiastic support of Duchamp's widow, challenges received ideas, misunderstandings, and misinformation