American abstract painter, born in Malden, Massachusetts. Began to paint abstract pictures while at Phillips Academy, Andover. Studied history at Princeton University 1954-58. Moved to New York in 1958, where a series of black paintings with lighter parallel lines was made followed in 1960 by an aluminium series, his first shaped canvases. First one-man exhibition at the Leo Castelli Gallery, New York, 1960, and started painting shaped canvases in 1961, using a great variety of forms and patterns, both regular and irregular. A friend of Andre and Judd, had considerable influence on the development of Minimal sculpture. His later work has included paintings with cut-out shapes in relief of irregular curves. In 1961 First exhibition in Europe, Galerie Lawrence, Paris, 1964, 1970 and 1994, Biennale di Venezia, 1970, and 1987 retrospectives, MoMA, 1985, ICA, London, 1995, retrospective, Reina Sofia, Madrid. Lives in New York.