For his first exhibition in London for more than a decade and a half, Sigmar Polke has chosen to present a major group of works on paper. It begins with examples of the earliest drawings and collages from his rarely-seen private notebooks and finishes with a magnificent new series of big paintings on paper done with poured metallic paint.

Polke is one of the most important figures of the generation which brought about the rebirth of German art after the hiatus of the Nazi period and the war years. Although his ironic and irreverent art has influenced the younger generation of British artists, this particular area of his work is almost unknown in London.

Born in East Germany in 1941, Sigmar Polke left the deprived Socialist East and came to the West at the age of twelve and later in the early Sixties attended the Kunst Akademie in Düsseldorf whence the influence of Joseph Beuys' teaching, with its mix of anthropology, science, politics and art, spread rapidly outwards. Düsseldorf was at the centre of Germany's economic miracle. American materialism and American art were widely promoted. The influence of Yves Klein and Fluxus was being felt and radical student groups were growing everywhere. Polke teamed up with other young artists, Gerhard Richter and Konrad Lueg (who became the influential gallery owner Konrad Fischer), in a movement they ironically entitled "Capitalist Realism". This was the background against which the new generation of artists had to seize the initiative and remake German art in their own likeness.

Polke's early drawings which flow through notebook after notebook reveal his thought processes and his awareness of them, his wonderful sense of humour and his ability to maintain a child-like freedom of spirit. Later he would present his ideas in increasingly metaphysical terms, but he has always had the capacity to slip through the humbug, traps and prejudices of society, armed only with laughter, the sting of truth and his fascination with and instinctive understanding of the human mind which tries to grapple with moral and instinctive decisions and to distinguish between the real and the fake and the essential nature of images and substances which continually transform and change.

He found inspiration first in the most ordinary places, where the imagination and subconscious meet: sea-side postcards and newspaper cartoons, in jokes about shoe-polish, drawing pins and lady wrestlers. He drew people with heads like potatoes and light bulbs and made fun of ties and sausages and sexual inhibitions. It is partly the basicness of Polke's early drawings which makes them so revealing. The magic and magnificence of many of the paintings is that the movements of the mind seem to echo those of the universe and the strange, even alchemical nature of their materials can conceal the other means by which he achieves them. But the lines in a Polke drawing are always manifestly lines of thought, weapons which cut through, revealing the thing drawn and the mind of the thinker and rendering them transparent. As with Duchamp and Beuys, there is something essentially masculine about those lines: wickedly precise, clever and subversive, these are manifestly the lines of the bachelor who strips the bride. Whether calm, euphoric or ecstatic, the thought processes which they represent can seem to flow as if Polke is channelling them from another outside source. But the artist never loses awareness, he is always the proverbial watcher who watches the watcher.

A retrospective of Polke's works on paper (1963-74) was shown at the Museum of Modern Art in New York in 1999. The exhibition subsequently travelled to the Hamburger Kunsthalle. The last major UK exhibition of Polke's work was held at the Tate Liverpool in 1995.