Prince of thieves

Would you be willing to pay £1.5 million for a framed photograph of a cigarette advert? Over the past two years, a couple of bold collectors have bid this price at auction for an enlarged image of a cowboy in the sunset taken from a Marlboro campaign. These are works of art by Richard Prince, from his celebrated Cowboys series. They are just copies, produced in small editions of two with one artist's proof, yet many museum curators and art theorists regard them as the most significant works of art of the past 30 years. Underpinning this intellectual and financial adulation lies the strange value system of contemporary art, with a logic entirely of its own.

Since the late Seventies, Prince has carved out a fashionable counter-cultural oeuvre based on what the art world calls "appropriation" and some of us might call theft.

The Serpentine's Prince show, his first-ever survey exhibition in Britain, is not as expansive as the Guggenheim's recent retrospective but it covers most of the main points of this intriguing artist's career.

Prince - now pushing 60 - began his artistic career as clippings clerk for Time-Life magazine in the late Seventies. There he cut out articles to send to researchers and was consequently left with a pile of adverts for Seventies luxury products. It was this job which led him to hit upon the idea for his first works. He photographed the ads without the logos and text and cleverly christened the activity "re-photography".

By the Eighties, "appropriation" was all the rage - feminist artist Sherrie Levine was framing cheap prints of Turners and signing them with her name, while Cindy Sherman was making Fifties-style film stills with herself as the star. At this time Prince's work could be both feminist and appropriationist. One work in the exhibition is the triptych of images of women all looking in a similar direction away from the camera - a simple but haunting representation of the contemporary feminist theme of the oppressive male gaze which turned women into eroticised performers. Prince covered different subjects using photographs as ready-mades. With the ads, he said he was interested in the images that "seduced us". His photos of American bikers, with their mix of customised technology and topless chicks, were more anthropological - a survey of the symbolic images and ceremonial objects produced by this subculture.

In the late Nineties, he began his joke paintings - high and low cultural forms collided in monumental paintings in which the naffest jokes of Middle America were stencilled over painted abstract surfaces. In I Know a Guy (2000), Prince inscribed "I told my mother-in-law, 'My house is your house.' Next week she sold it" on top of floating pastel washes. The joke paintings are an intellectually hypnotic combination of opposites which hold one's mind like a piece of metal suspended between two magnets.

Then there are the car bonnets. Prince spotted that the mottled or gleaming surfaces and organic shapes of these car parts were as attractive as much of the contemporary art around. He finished them off with filler, and rounded out their forms with wood and fibre-glass. He hung them up like paintings or made floor-standing fetishistic objects out of them.

In his nurse paintings, Prince took the covers of an obscure genre of American hospital pulp fiction and printed them big on canvas. He painted over the titles with drippy crude brushstrokes, and always added a surgical mask over the nurse's mouth. He was using painting to literally tart up pulp fiction as fine art.

Many artists have surfed the contemporary art boom but Prince has surfed the biggest wave of them all. In 2003, you could have bought one of his nurse paintings for around $100,000. In May this year, Man Crazy Nurse II was auctioned for $7.5 million.

In his most recent work, Prince has covered a big American classic car with prints of sexy girls and begun a series of paintings in which he over-paints pornography in a Picasso-esque style. They look at first like a drop in quality, a reworking of old formulae - but that's what his fans said about the nurse paintings five years ago. Princes have a habit of growing into kings.