During the two decades between 1946 and 1966, when the world at large had long since considered that he had given up "art," Marcel Duchamp worked quietly in his New York studio, on the top floor of a building at 210 West 14th Street, on the fabrication of a large and complex tableau to which he gave the title: Étant Donnés: 1? la chute d'eau, 2? le gaz d'éclairage… (Given: 1? the waterfall, 2? the illuminating gas…). When his work was completed, he inscribed its title, the dates, and his signature on the right arm of the nude female figure that constitutes the central element of the tableau, and proceeded to prepare an illustrated manual of instructions for the use of anyone needing to take the assemblage apart or to reassemble it. The manual of instructions, contained in a looseleaf binder, is dated by Duchamp to 1966.

Before Duchamp's peaceful, unexpected death in Paris on October 2, 1968, at the age of eighty-one, Étant Donnés… was acquired by the Cassandra Foundation. Later that year, in accordance with his wish, the Foundation presented it to the Philadelphia Museum of Art, where it joined the largest collection of Duchamp's work in the world. …

Duchamp's instruction manual proved essential to the task of moving the assemblage, which had been previously transferred by Duchamp himself to a small room in a commercial building at 80 East 11th Street when the lease on his 14th Street studio expired. Following his instructions, Étant Donnés… was dismantled in New York, carefully packed, moved to Philadelphia, and reinstalled in the Museum gallery prepared for it. By July 7, 1969, the reassembly and installation were complete, and the public entering the gallery hung with Duchamp's paintings and centered around The Large Glass could now continue to the little room beyond it and (one by one) contemplate the artist's last major work through a pair of holes in a weathered, wooden Spanish door, framed by a brick archway set in plaster wall. …

In his title page for the manual, Duchamp refers to Étant Donnés… as an "approximation démontable" (an approximation that can be taken apart, or disassembled), adding that in using the word "approximation" he intends to convey a margin of ad libitum in the assembly and disassembly of his construction. Those who scrutinize this volume will find that the position of the cotton clouds in the sky is "ad lib," and that the degree of brilliance of the little waterfall can be adjusted by slight shifts in the position of the wooden bar that supports a biscuit box containing a round fluorescent light. Such niceties lend characteristic charm and an air of enigma to this matter-of-fact guide, which makes no attempt to explain or elaborate upon the meaning of Étant Donnés…, but simply leads step by step through the process of putting the assemblage together. Duchamp illustrates his manual liberally with his own photographs, plans, and drawings, all, insofar as it is possible to judge, created specifically for the purpose of making his instructions as clear as possible, and in no way constituting preliminary studies and sketches. In fact, it seems evident that the probable order in which Duchamp himself worked upon elements of the tableau over two decades--first the landscape background and the nude figure, then the overall construction and the lighting--is not particularly reflected in the order of the fifteen "operations" that Duchamp set down for its reassembly....Anne d'Harnoncourt, from the introduction to Manual of Instructions for the Assembly of Étant Donnés… (1987).