When is a urinal no longer a urinal? When Marcel Duchamp (1887–1968) declared it to be art. The uproar that greeted the French artist´s Fountain (1917), a porcelain urinal installed in a gallery, sent shock waves through the art world establishment that reverberate right through to today. This essential introduction distills all the daring and the scandal of Duchamp´s practice into one essential overview not only of a pioneering creative but also of a critical moment in Western culture. From his groundbreaking blend of abstraction, Cubism, and Futurism in Nude Descending a Staircase (1912) to his forays into the now-iconic “readymades” such as Bicycle Wheel (1913) and Bottle Rack (1914) we explore how Duchamp consistently challenged the notion of what art is and, in so doing, opened up a world of conceptual possibilities beyond the “retinal” experience.