In all his work, French visionary Marcel Duchamp (1887-1968)--Dadaist, Surrealist and progenitor of conceptual art--challenged the traditional dichotomy between original and copy. By replicating his own creations, with variable dimensions and in limited editions, Duchamp radically redefined what constitutes an artwork and, by extension, the identity of the artist. This volume places at its center the Boite en valise No. 1 in the Peggy Guggenheim Collection. Tellingly signed "From or by Marcel Duchamp or Rrose Selavy," the portable gallery contains 69 small-scale copies and color reproductions and photographs of the artist's principal works with additions in pencil, watercolor and ink. The concepts of double, original, copy and replica are discussed and analyzed through numerous works from some of the world's most important museums and several private collections.