Photography: William Klein

William Klein has the reputation of being a difficult man, someone who does not suffer fools gladly. But today he is revealing himself as both gracious and generous with his time. He is even enjoying having his picture taken - like most photographers Klein usually hates being at the other end of the lens.

Standing in his Left Bank apartment in Paris, which he shares with his wife and collaborator Janine, he poses calmly, looking like a clean-cut college kid in his jeans and trainers, as the photographer energetically jumps around the tripod.

Despite living in Paris for nearly all his adult life and his successful parallel careers in making movies, abstract art, and fashion photography, William Klein is best known for the book of his black and white photographs taken in the city of his birth, New York. First published in France in 1956, it is still a major source of inspiration for both photographers and film-makers. The book is entitled New York is Good and Good for You: William Klein trance witness revels. It might also have read ... the chance witness reveals, for both phrases sum up what he thinks of photography. It is a moment of "trance" when you can capture hundreds of things that are happening at the same time

and which you feel and see consciously or not, and also a moment of "chance". And Klein both revels in, and reveals, the world to us.

Klein has never been interested in photographs that just tell a story; he came from outside the discipline, with an interest in abstract art and graphic design. Even his earliest photography experimented with long exposures and graininess. For him the results were always a surprise.

He was born into a middle-class New York Jewish family in 1928, growing up in a rough neighbourhood. He and his school friends would roam around the collections at MoMA (the city's Museum of Modern Art) and, in the cinema downstairs, see films by Fritz Lang. His friends had cameras and even labs at home, and he found his first introduction to photography magical, but also a world somehow outside his realm.

In 1948 Klein was sent to occupied Germany as a US soldier, and it was here that he got his first camera, won in a poker game. After serving for one year, Klein decided to stay on to study fine art in Paris - including a brief period with the artist Fernand Leger - and while in the city he met and married his wife, Janine.

But in 1954, Klein returned to the States where he started making abstract art. On the strength of this work Alexander Liebermann, the artistic director of American Vogue, suggested that Klein become his assistant at the magazine. They both quickly realised, however, that Klein, with his restless and explosive energy, would not last five minutes in an office. Instead Liebermann asked him to come up with a photographic project and then gave him a contract, with an expense account for film and paper to print his pictures. For Liebermann it must have been an extraordinary act of faith in someone who, at 25, had all kinds of ideas but no portfolio to back them up.

Klein's idea was to make a photographic journal of New York, "with one American eye and one European eye" as he puts it. He knew instinctively that this fresh way of looking at his native city after years of absence in Germany and France would quickly wear off. He went to work fast.

Capturing his vision of New York, which Klein calls "the world capital of anguish", was six months' work, on and off, in 1954 and 1955. Photographing the street life of the city was "a kind of nostalgia for New York, for my lost youth," says Klein, plus a discovery of unknown parts of the city. As a child he had never been to the black enclaves of Harlem or Queens and much of what he knew of the area outside his immediate neighbourhood came from books and films.

Klein turned the bathroom of his small apartment into a lab and used expensive double-weight paper, never making rough prints first. He says that the pictures he fished out of the bathtub "knocked me out".

His images came from the thick of things. He was often working down on the pavement at the eye-level of the kids he was photographing. Robert Capa famously said that if your photographs were no good it was because you were not close enough, and in Klein's New York people press themselves up against the lens, dancing around the photographer, pulling faces, pretending to shoot each other, or the photographer, with toy guns. It is the kind of photography that is impossible to do today: people are no longer delighted to be snapped in the street, do not dance or horse around in Harlem on Easter Sunday for a photographer. They were intrigued by this white guy with his beautiful French wife.

However, the apparent chaos, the constant motion of street life, is beautifully and rigorously organised, the frame filled with the maximum of different actions and emotions, people staring at each other, at the photographer, or something out of the frame. Klein's sense of composition was new and innovative.

When Klein offered the Vogue project - intriguingly, the magazine never ran any of the photos - to US publishers nobody was interested. Even when it first came out in France - where Klein had settled again - some reactions were strongly against it. For many people this was not photography, nor was it New York. And it was certainly not in the tradition of "concerned" photography - the subjects of Klein's work are not the suffering victims of a cruel world. But when Federico Fellini saw the book he employed Klein as an assistant. Although the film project fell through Klein produced a book about Roman street and beach life, followed by two more on Tokyo and Moscow.

Now 70, Klein still splits his time between his photographic studio, the space where he paints and the cutting room where he works on his latest film, Handel's Messiah. Made in the US and France, it uses the music of the Messiah from beginning to end, sung by prison choirs, the Dallas police force, people in drug rehab - a cast of thousands.

Klein still has the same passionate curiosity about the world that he had as a young man, and is still the chance witness who revels in and reveals our world to us

`William Klein: New York' is at the Scottish National Portrait Gallery, 1 Queen Street, Edinburgh from 23 October 1998 to 5 January 1999