Critical biographies of contemporary American painters are all the more welcome for being rare, and all the more disappointing when they fail. Philip Guston's reputation is clouded at the moment but his career--highschool insurgent with Jackson Pollock, federally-sponsored, Mexicaninspired muralist, stalwart of social consciousness, prominent Abstract Expressionist, brut satirist--is both representative and individual, and could repay attention. Not, however, the way Ashton construes it--as the outcome of looking long at Uccello and de Chirico, reading Kafka and his inspiration Flaubert, thinking about Max Beckmann, steeping himself in Baudelaire and Watteau, in Camus and Dostoevsky, and so on and on. The intervening observations about Guston's work are often clumsy and pedantic, the general remarks tend to be empty effusions. ""Abstraction was an intoxicating experience. Like a glider pilot, he could not resist the silences and unknown spaces he had never known before. The rules that had once contained his imagery had fallen away."" About Guston's fellow-artists, similarly positioned, Ashton has almost nothing to say. Too bad.