Tom Wesselmann was one of the key members of 1960s American Pop Art in New York, a movement that started in England in the 1950s. His work is now considered iconic for the period and has fetched more than $10 million at auction, and his work is represented in the major museums of the world. His paintings, often in shaped canvases and with collage, are considered important examples of American 20th century art. This work depicts his favourite model of the 1990s, Monica Serra, who is herself an artist (and singer). Similar works on paper have made up to $43,500 at auction.

"Wesselmann liked to say that his work explored the gap between art and life, a remark neatly brought to life at a New York exhibition when a visitor, confronted by a collage containing a real ringing telephone, demanded, "Won't someone please answer that phone?" It's a story repeated often enough to be untrue, and, anyway, not one of which Wesselmann would have approved: he always insisted that the objects he usurped were stripped of utility by their transformation into artworks.

The American art historian Lucy Lippard classified Wesselmann the five "hard-core" New York pop artists, with Warhol, Lichtenstein, Rosenquist and Oldenburg. The phrase encapsulates the flip and brash promiscuity of his imagery: the 100-piece Great American Nude series of the 1960s, with flat billboard colours and faceless but curiously erotic naked women painted with ruby Mae West lips; the still lifes, kitchen interiors with refrigerators, wireless sets, paper towels, bottles of beer and 7 Up; the landscapes, flat, abstracted, and little more than coloured backdrops for, say, a full-size cut-out of a VW Beetle. The genres are interchangeable, and the imagery is common to a lot of pop art from Richard Hamilton in Britain to Warhol and Mel Ramos in the US: ice cream sundaes, toasters, bathroom taps, loo seats, containers of air freshener, and - also objects - big-boobed nudes. But Wesselmann insisted on the individuality of all the artists involved in pop art and the lack of a group identity.

Wesselmann was drafted into the forces in the early 1950s and, in defence against "the horror of army life" as he put it, began to draw cartoons. He left the army with the half-formed desire to be a cartoonist and in 1956 he enrolled at the Cooper Union for the Advancement of Science and Art in New York. By his last year there, 1959, he had become a painter, though not at first a very good one. His initial influence was the venerable abstract expressionist Willem de Kooning; although he soon realised that this was a false start, he retained from de Kooning's work a sense of how to fill the picture surface with incident, to push at the edges. He began to work in collage, sometimes with actual three-dimensional objects. A piece of rug would be the floor in a painting of an interior, a piece of wallpaper the wall, a reproduction Matisse or a Mondrian would be a picture on the wall.

In 1960 he began the Great American Nudes, which remain his best-known works, and in 1961 the Green Gallery on 57th Street offered him a contract. Not until this point, apparently, did he realise he was independently working a seam already being mined by other artists fed up with the controlling influence of the abstract expressionists and their Dr Miracle, the critic Clement Greenberg.

Wesselmann's early work was quite crude and small enough for him to create on a drawing board perched on his lap. As he grew more confident and expert, and the compositions became tightly controlled, his paintings often expanded, of necessity, to the size of the billboards whose elements they incorporated: the VW landscape was more than 12ft wide. The paintings that he appropriated, the Matisses and Mondrians, were there to signify that art had lost its uniqueness, had become a part of the mass production society: in effect a visual representation of the argument that the writer Walter Benjamin had made before the second world war, in which he had concluded "that which withers in the age of mechanical reproduction is the aura of the work of art". Wesselmann, however, maintained that in his own work all the subsumed elements became part of paintings that were uniquely "charged with their very presence".

Sometimes his colours are arbitrary, as indeed they are in commercial art, and the composition so tight that they become immobile, although charged with static electricity. At other times, especially in the nudes, rogue elements of fine art produce their own ambiguity: against a white strip that seems at first to be a bikini against the pink of flesh, a delicately airbrushed suggestion of pubic hair simultaneously shocks and create an erotic charge, indicating that the white strip is not the bikini bottom, but an area of skin protected from the sun.

Later Wesselmann did paintings that directly referred to art history: a white-on-white surface that, at a close look, is actually a shallowly modelled representation of one of the Bakelite wireless sets that he used so often (they were old-fashioned even in the 1960s, but Wesselmann denied nostalgia, insisting that objects were just objects and there to be transformed). In the 1980s he began to work in aluminium and enamel, adapting the clean lines of his earlier paintings, and at the time of his death he was working on nudes painted with some of the freedom of abstract expressionism. It seems that he never really exorcised the ghost of de Kooning."

Written by Michael McMay, The Guardian, 2004