BERNARD MALAMUD'S new novel Dubin's Lives , years in the writing, is, as everyone expected it would be, a major work, comic, philosophical, and poetic; a book no reader of either serious literature or books of prurient interest will want to miss.

The subject is "middle-age crisis." William B. Dubin, biographer, has come to that time of life when surgeons suddenly wish they could be circus clowns, and husbands fall in love with younger women. Except for the ending, on which more later, the plot is so familiar it needs no summary: extramarital relations, psychological struggle. But this is not to say that Malamud has written a commonplace, predictable book. Dubin's Lives has the same fundamental plot as all those other books because, like all significant writers, Malamud is interested in exactly what everyone else his age, and of his Age, is interested in. The difference is that Malamud develops the subject with brilliance and almost Melvillian doggedness, leaving no philosophical or psychological stone unturned.

Nothing in Dubin's Lives exists to serve plot, character, setting, or philosophy alone: every detail serves doubly, triply. Sooner or later almost everything one might think of to say about spiritual or physical identity -- one's own and that of others -- Malamud finds some concrete, dramatic way to say. Dubin is not just any man in middle-aged crisis but a biographer, a professional explorer of other people's lives (he has written on Thoreau, Twain, etc., and is now at work on D. H. Lawrence, a man as passionate and confused as William Dubin). Dubin falls in love with not just any more-or-less-beautiful young woman but one desperately trying to find herself, discover who she "is." Dubin's father was a lifelong "waiter" in both senses; his mother, after the early death (truncated biography) of Dubin's brother, was a schizoid madwoman. Though Dubin is in a crisis of search-for-the-self, the self he has appeared to be has to some extent defined and wrecked his two children (whose natures he struggles in vain to understand).

The novel's symbolic richness is all but inexhaustible. Like Einstein's bent universe, circling endlessly on its self and possessing no center -- and like Dubin's life, meditations, and mistakes -- Dubin's daily walks in pursuit of health, youth, adventure, and Thoreauvian oneness with nature are circular; Malamud compares the walks to the movement of an often-played record on a turntable. (In the final scene, music by one of Dubin's subjects, Mozart, everlasting spokesman of youth, is on the record player.) All of the biographies Dubin reads and writes are carefully chosen to throw light (and dazzling quotations) on the central identity question. Needless to say, the names of Malamud's characters, like everything else, work symbolically. For instance: Will-I-am (Dubin's pun) B. ("be") Dubin ("ich bist Du-bin," Dubin quips). It should also be needless to say, I imagine, that on one level -- not the most profound -- Dubin's Lives, like Pictures of Fidelman and almost everything Malamud has written since, is an exploration of art and the artist.

Trying to summarize the "ideas" in a novel like Dubin's Lives would be madness: they fly up like partridges, and, more important, they are novelistic ideas, urgently explored but never fully resolved, usually because they can't be. The end of the novel is ambiguous, unsettled. Dubin is faintly toying with living three days each week with his mistress, four with his wife (we strongly doubt that he will do it: he'll go on as he is, getting away with things); his mistress, who has suggested the idea, calls out her window as Dubin runs toward home, "'Don't kid yourself!'" What she probably means is, "You love me more than you love her"; but we know he loves both and neither, and, more important, we are reminded that it is Dubin's nature to kid himself: for all his will and intellect, he's a man almost infallibly wrong -- at times, in fact, a swine. As Dubin runs home in these final lines, the man who really loves Dubin's mistress, and has every right to be loved in return stands spying from the trees, watching other people's lives like a biographer (Roger Foster is his name, foster child of the universe, peeking helplessly from behind a double phallus, "a long-boughed two-trunked silver maple" (boughed and bowed). Dubin, running home -- completing the usual circle of his walk -- is like a conquering hero, but his victory is comic, even slightly repellent: "Dubin ran up the moonlit road, holding his half-stiffened phallus in his hand, for his wife with love." Some love! But Dubin partly knows it. Asked by his mistress if he loves his wife, he has answered, "'I love her life.'" If he's a hero as well as a fool it's because, though he knows better, he refuses to let go of the delusion that a man can live multiple lives. Early in the novel Malamud writes, "Dubin in his heart of hearts mourns Dubin." Now at the end, Dubin in his life-greed celebrates Dubin: I am because you were. One might perhaps do worse.

No living American writes better than Malamud at his best, and much of Dubin's Lives is Malamud at his best. We get in this novel not only masterful realistic scenes but also some of the finest dream sequences, scenes of mistaken perception, and mad scenes anywhere in recent fiction. Early in the novel, Dubin looks out with pleasure and sees his wife unexpectedly dancing below him on the lawn. (She once studied dance, he remembers.) "'Hap-pee!'" he hears her cry up to him. "'Wonderful!'" he shouts back. It turns out she had a bee inside her blouse and was yelling to him for help. Later, in wintertime, a man, a total stranger, mysteriously joins Dubin on his walk, and for no clear reason, walks close to Dubin, sometimes bumping his elbow. The man will not talk, and Dubin, somewhat baffled, decides to put up with it. When birds fly over, the man raises an imaginary gun and says "'Bang bang.'" After a while, two crows fly over, the man drops to one knee with a grunt and raises his arms as though sighting up a gun barrel, and roars "'Boom boom.'" Malamud continues:

"To Dubin's astonishment one of the black birds wavered in flight plummeted to the ground. The stranger let out a hoarse shout and plunged into the white field to retrieve the crow. Holding it up for Dubin to see, he pressed the dead bird to his chest and awkwardly ran, kicking up snow, diagonally across the field in the direction he had come.

Can a crow have a heart attack?

One of us is mad, the biographer thought."

I think it should be added that no one in America writes worse than Malamud at his worst. Not too much need be made of this, perhaps. Very serious novelists (Tolstoy, Melville) can afford to make mistakes not permitted to novelists of the second rank, that is, masters of elegant style and construction but no deeply booming thought. One typical Malamud mistake is easily forgivable. He frequently abandons verisimilitude and psychological credibility because he cares more about ideas than about how people really talk. Dubin can spin out off-the-cuff lectures (mostly to his mistress) so elegant and bookish, so logical, tightly constructed, and to the point, that Dr. Johnson himself, if he could hear them in real life, would fall on his rear end in astonishment. No serious reader will much object. When the argument is interesting, reality be damned.

Other Malamud mistakes are less excusable. Though he can write like a master, he can also turn off his ear and write (speaking of a cat): "It was a long-bodied lithe almost lynx-like male, with an upright head and twitching tail." One section of the novel -- a brief slump in the middle -- is written in an arch, coy, superliterary style reminiscent of the early style of Malamud's neighbor and Bennington colleague Nicholas Delbanco. (Delbanco, after passing the disease to Malamud, got better.) Dubin's wife frequently talks pure early-Delbancoesque: "'And I have the feeling that in her death I am diminished.'" None of Malamud's characters dares to speak such ordinary American as "I don't know many"; they say, prissy and fancy, "I know few." The omniscient narrator does the same, especially when he gets on the weather. One winces and hurries past. Ever since Joyce, mannerism has been the leaky valve in the heart of our serious fiction, but Malamud's particular mannered style suggests a character fault: like Dubin, he kids himself.

It ought to be said in Malamud's defense that no one who dares as much as Malamud does can expect to move as surely as the stylist who keeps watching his feet. The imagination behind Dubin's Lives is, like Stanley Elkin's, awesome, downright eager to take risks. We get one crazily original scene after another: 59-year-old Dubin peeking in through his mistress' window, a man terrified to near-madness by dogs, fighting off his mistress' dog; Dubin, having slipped off his circle, helplessly wandering in a magnificently cently realized blizzard, a mile from home but close to death; old Dubin in a tree while an angry farmer shoots blindly into the night, heart set on ending his biography. The novel is rich and intelligent, entertaining on many levels. Yet it leaves me uneasy. Because Dubin is in certain ways courageous, also because Dubin tries hard to be honest, though he can't be, Malamud seems to admire him more than he deserves. Though he treats Dubin as a comic hero, a deluded man, one keeps suspecting that Malamud is solidly on Dubin's side, not loving him though he laughs at him, but instead, winking and leering at the audience, faking ironic detachment as he sneaks William Dubin onto the pedestal, a moral sex-hero, Falstaff with a face-lift, so that everyone will think he's Prince Hal.