Philip Guston as an artist went through three distinct phases. First there was the accomplished Neo-Romantic of the 1930s and 1940s, strongly influenced by Beckmann and de Chirico, but also part of an American generation which reacted to the grimness of the Great Slump and to urban poverty and degradation. In this, Guston belonged in the same camp as Ben Shahn and other artists with a social conscience, who in general inclined strongly to the Left, though he was younger than the majority. Like many of them, too, he was Jewish by blood - born Philip Goldstein in Montreal in 1913, the son of Russian immigrants.
The second phase, and the one which made him an international figure, was as an Abstract Expressionist or "Action Painter". Guston did not have the sheer scale and energy of Jackson Pollock or the visionary dimension of Rothko, but for many of us he was the subtlest painter of the entire New York School. His drifting, multi-tiered mesh of colours and half-glimpsed shapes were a big influence on the younger generation, even if the wider public preferred de Kooning or Franz Kline, or even Gottlieb. He was, in fact, rather a painter's painter and he made a strong impact on emerging European artists such as Baselitz, whose style could hardly have taken shape without him.
Guston, we thought then, was the one among them all who would last best, the one to watch. So we were horrified when this cultured stylist almost overnight switched horses and began to paint - and draw - in a kind of deliberately clumsy, mock-naive, cartoonish manner which seemed to parody all he had achieved or stood for up to then. What had made him embrace such ugly kitsch - was it an inner impasse, some emotional, private crisis, or just a failure of self-belief? His notorious 1970 exhibition in New York was damned by almost all the leading critics and sold badly; Hilton Kramer summed it up in the New York Times by saying that it was a case of "a mandarin pretending to be a stumblebum". Guston was devastated by the negative reaction and left for Rome and Europe, where he stayed for nearly a year. He did not abandon his new style, and explained to the critic Harold Rosenberg: "Naturally, I'm very involved with the culture of painting; nevertheless, getting involved in the painting means to divest myself continuously of what I already know and this gets you into an area of, well, you call it crudeness, but you see, at that point it's not crude to me. I just want to realise a certain subject."
At that time Guston was already suffering from the early stages of a heart condition and he died in 1980, but by then the tide had turned in his favour. Followers of the New Expressionism and what was called Bad Painting found in him a major signpost, and his late paintings and drawings were a potent influence on a whole new generation; only Picasso's last paintings made a comparable impact. These strange works - obsessive, self-aware, blackly humorous, simplistic yet sinister - have opened up a new path for both painters and graphic artists. Guston's "third period" may not be his greatest or most appealing, but it went farthest into the future.