American painter, and one of the world's best photographers, born in Philadelphia. Worked in an advertising office and then part-time as draughtsman for publishers of books on engineering, atlases and maps. Met Duchamp in 1915 and collaborated with him in initiating a proto-Dada movement in New York. First one-man exhibition at the Daniel Gallery, New York, 1915. Began to make abstract paintings in 1916, with flat forms and vivid colours, and also experimented with airbrush paintings and sculpture-objects. Moved to Paris in 1921, was introduced by Duchamp to Breton and his circle, and became a pillar of the 30's and of the Dadaism. Participated in the Dada and Surrealist movements with paintings, assemblage-objects and photographs. Mainly active for some years as portrait and fashion photographer, and as pioneer of new photographic techniques such as rayographs and solarizations. Painted regularly again from the mid 1930s, at first in an illusionistic style inspired by de Chirico and Magritte. Spent 1940-51 in the USA, living in Hollywood, then in 1951 returned to Paris. Died in Paris.