IN THE GREAT galaxy of 19th-century Russian writers, Turgenev has always struck Western readers as being, next to Chekhov, the sanest of the lot. Unlike his contemporaries Tolstoy and Dostoevsky, Turgenev was not a semi-mad ideologue preaching visionary religious and nationalistic dogmas. On the contrary, perhaps because of his many years of self-exile in the West, he seems more akin to George Eliot, Flaubert and Henry James, all of whom he knew personally.

Yet his career had its share of Slavic furor. His father died when Turgenev was 16, leaving the tall, handsome, but inordinately sensitive youth in the dubious care of a truly monstrous mother who thought nothing of whipping her serfs (she had 5,000 of them) on a whim and humiliating her sons beyond all endurance. Hunting alone on her vast estate was one of the few consolations available to the nature-loving Turgenev, ultimately inspiring his first book, the Sportsman's Sketches, which later impressed no less mighty a hunter than Hemingway as the finest literary treatment of the subject. The sketches in it also displayed Turgenev's inveterate opposition to serfdom, which eventually won him a month in prison and years of house arrest.

Much of his life Turgenev spent hopelessly trailing about Europe in the train of the much-acclaimed and sensationally ugly Spanish opera singer Pauline Viardot-Garcia and her husband Louis Viardot in what surely must have been one of the strangest - and longest-lasting - menages a trois of the century. Pritchett doubts that the affair with Pauline was ever consummated. It strikes our more sexually impatient age as most peculiar that a man as great as Turgenev should have squandered so much of his time and psychic energy essentially playing the role of a stage-door Vanya, but, Pritchett's psychological acuity and elegance of style are nowhere more evident than in his assessment of the situation: "Although Turgenev made bitter remarks in the vicissitudes of his attachment to her and in his masochistic way said that he lived under her heel as many of his incredulous friends thought, he endured what he did endure because he was in love with his own chivalrous love."

This gentlest of men also managed to get into obscurely rancorous quarrels with Tolstoy and Dostoevsky; he aroused the paranoid wrath of yet another contemporary, Goncharov, author of the single masterpiece Oblomov, when Goncharov - not without reason - accused him of plagiarism. And Turgenev's own masterpiece, Fathers and Sons, which remains the greatest fictional treatment of the "generation gap," aroused the fury of young and old, of Slavophiles and Westernizers, of political Left and Right alike, a tribute to Turgenev's unremitting fair-mindedness, but one which deeply wounded his vanity.

For Turgenev was not without his eccentricities. He was vain and hypochondriacal, a valetudinarian at the age of 35 who was convinced "that he had a thinner skill than other men," when in fact he only had a thinner skin. He fathered two illegitimate children, foisting one on the Viardots and abandoning the other to an orphanage; as Pritchett wryly points out, "Fatherhood . . . was not one of Turgenev's gifts."

These lay rather in the production of such exquisite fictions as Rudin, First Love, Smoke and Virgin Soil - novels and stories which, for all their relative thinness and restriction of range, show every sign of enduring as long as their more massive rivals, War and Peace and The Brothers Karamazov.

Pritchett is at his finest when analyzing these hauntingly pastel renditions of Russian country life, with their ineffectual men and frustrated women beginning and ending affairs but rarely ever consummating them. Pritchett is also unfailingly acute and illuminating when comparing Turgenev's art to the art of his contemporaries.

But "biography," he confesses, "has the fundamental weakness that it can rarely tell us what was said or unsaid between the parties: it is a novel without dialogue," and here he disappoints, at least, in comparison with another recent biography of a great Russian writer, Ronald Hingley's A New Life of Anton Chekhov. Pritchett announces at the outset that "There has not yet been a definitive biography of Turgenev in any language," which leads one to believe that he will fill the gap. Then he admits, with an aplomb that perhaps only an Englishman can summon up, that he has no knowledge of Russian and will be dependent solely on English and French sources.

The result is an elegant bio-critical essay, rather than a full-dress biography. Years of Turgenev's admittedly uneventful life are passed over quickly. Pritchett doesn't even bother to quote the famous deathbed letter Turgenev wrote to Tolstoy imploring him to abandon his various socio-religious manias and return to his great art. The letter may be a cliche of Russian literary history by now, but one nevertheless would like to see it in a "definitive biography." Instead, the book ends with an unfortunate misprint alluding to "Countless Tolstoy's children." Considering the number of children the poor Countess bore to her importunate husband this has certain Freudian piquancy, but it is hardly a substitute for one of the noblest letters by one of the noblest writers in the Russian language.