By MICHAEL PEPPIATT

THE SHAMEFUL LIFE OF SALVADOR DALI

By Ian Gibson.

Illustrated. 798 pp. New York:

W. W. Norton & Company. $45.



y the time he became a household name, Salvador Dali (1904-89) was already perceived above all as a performer -- an outrageous self-publicist and witty clown. In France, where he spent part of the year, he could always be relied on to liven up any event or public debate. But even in that role, he began to pall. I remember almost bumping into him in 1971 at the Francis Bacon retrospective at the Grand Palais in Paris. He was unmistakable, with his manic stare, pointy mustaches and full-length fur coat. ''They're very, very raisonnables,'' Dali repeated loudly to those around him, pointing his silver-topped cane at the most alarming of Bacon's images; and he was visibly annoyed when this bit of Surrealist upstaging failed to turn more than a few heads.

The story of how Dali went from the subversive brilliance of his youth to an increasingly hollow, money-making exhibitionism is told with exemplary clarity in Ian Gibson's big new biography of the Catalan artist. It is ultimately a depressing tale, because it chronicles in great detail how Dali progressively cheapened and squandered his enormous talent. Gibson concentrates on Dali's early career, because it is far and away the most interesting. ''Two-thirds of this book,'' he declares, ''are devoted to one-third of Dali's life. Such a structure was not imposed artificially, but shaped itself irresistibly as my research progressed. Dali's work, after he moved to America in 1940, grows increasingly hackneyed and repetitious.'' And the man himself, Gibson might have added, became increasingly grotesque.

Signs of the ruthless manipulation and self-aggrandizement that characterized the later Dali were discernible in his youth. When he was barely 16, for instance, he announced in his diary: ''I'll be a genius, and the world will admire me. Perhaps I'll be despised and misunderstood, but I'll be a genius, a great genius, I'm certain of it.'' Slim and strikingly handsome, he let his jet-black hair grow down to his shoulders and began dressing in stylishly bohemian clothes. Although paralyzingly shy, the adolescent Dali was already firmly set on his conquest of the world.

Gibson begins his book with a full description of Dali's forebears and the area north of Barcelona, around Figueres and Cadaqués, to which the artist, forever conscious of being Catalan rather than Spanish, was to remain so deeply attached. Dali's childhood comes across as relatively normal (above all if one discounts his own later, myth-making version of it), except that he had an older brother, also called Salvador, who died some nine months before Dali was born. His parents, who were comfortably well off and relatively cultivated, made all the more fuss over him, giving in to his every whim. But even at a very early age, according to Gibson, Dali suffered intense feelings of shame, making it ''extremely difficult for him to maintain normal relations with the people around him.''

Other signs that Dali was not just any boy growing up in provincial, middle-class Catalonia were not long in coming. Extreme timidity coincided with an array of obsessions, such as buttocks (fascination with, both male and female) and locusts (pathological fear of), that persisted throughout his life. In adolescence, Dali also became fixated on his unusually complex sexuality. First, he realized that he was poorly equipped for intercourse. However disturbing the discovery, he related it with typical verve: ''For a long time I experienced the misery of believing I was impotent,'' he observes in his ''Unspeakable Confessions.'' ''Naked, and comparing myself to my schoolfriends, I discovered that my penis was small, pitiful and soft. I can recall a pornographic novel whose Don Juan machine-gunned female genitals with ferocious glee, saying that he enjoyed hearing women creak like watermelons. I convinced myself that I would never be able to make a woman creak like a watermelon.'' The other discovery was normal -- except that, for Dali, masturbation was to be the main, indeed almost the only, sexual activity right through his life.

These facts would hardly be relevant if they were not vital to an understanding of Dali's subsequent behavior and his art. An overriding sense of sexual inadequacy was surely one of the factors that drove him to create with such single-minded intensity; and most of the self-styled Great Masturbator's best paintings bristle with erotic allusions. Gibson rightly emphasizes Dali's tortured sexuality, and in an intriguing passage he examines what appears to have been a protracted but unconsummated love affair with the poet Federico García Lorca, whom Dali later described as the greatest friend of his youth.

Dali's other close companion during this period was Luis Buñuel. Gibson's account of the immediate bonding and rivalry of this fabulously talented Spanish trio, who had come together as students in Madrid, is one of the most exhilarating passages in the book. It seems almost uncanny that the three most artistically gifted young men in the country should have met and had time to share their dreams, thus influencing one another for life. Gibson gives a tantalizing glimpse of García Lorca, whose biography he has already written, and records with gusto how Buñuel and Dali came to make their subversive first film together, ''Un Chien Andalou,'' which was shown in Paris in 1929. The lively friendship of the three was not to last. Garcia Lorca was put to death early in the Spanish Civil War, and Buñuel was alienated by Dali's shameless volte-face when, on his return to Spain in 1948 after 10 years in America, he declared his unconditional support for Franco and Roman Catholicism.

Two events in the late 20's shaped the rest of Dali's life. One was his conversion -- the word is not too strong -- to Surrealism, which took place (if Dali's own unreliable memoirs are to be believed) when he met the movement's leader, André Breton: ''I felt at the time that I had been granted a second birth,'' Dali stated many years later. ''The Surrealist group was for me a sort of nourishing placenta and I believed in Surrealism as if it constituted the Tables of the Law.'' As he describes Dali's new involvement, Gibson also conjures up the effervescence surrounding the movement, with its constant battles, internal and external, and its fierce resolve to turn all preconceived notions about culture and life on their heads. For a while Surrealism's ideology kept at bay the egomania and self-serving cynicism that later claimed the artist entirely.

A different involvement, however, began from its outset to egg them on. Helena Diakanoff Devulina -- familiarly Gala -- appears to have dominated Dali, fascinating and terrifying him, from the moment they met in 1929. She was then married to the poet Paul Éluard, but the couple accepted and even encouraged each other's infidelities, to the point where Gala felt that Éluard was pushing her at his friend Dali. She left Éluard to live with the painter. For Dali, the highly sexed, Russian-born Gala brought some form of physical release and the promise of intelligent companionship; for her, the artist seems to have been a career and a fortune waiting to be made, as well as a husband who would tolerate all the lovers she craved. In the end, they seem to have been a monstrous match for each other, and much of the latter part of this biography traces their mutual degradation.

On the way, there are moments of respite. Dali's visit to Freud, for instance, is a vignette that seems suddenly to speak volumes about the 20th century. And with his incredible energy, Dali carries even the growing weight of his empty clowning and image-making before him. As the money poured in -- from paintings, endless prints and all kinds of merchandising -- the artist surrounded himself with a court of beautiful young people and managed to meet virtually everyone who took his fancy, from Pope Pius XII and Franco to Clark Gable and Bob Hope. Once Gala died in 1982, Dali went into rapid decline, and his own end was as gruesome as this master of unpleasant fantasies might himself have devised -- preyed on by his closest advisers and abandoned by those who were paid to look after him in his decrepitude. Nevertheless, one wonders whether he was in fact as ashamed of himself as his biographer claims. It hardly matters. The book provides not so much a cautionary tale as a trustworthy, even-handed account of a life that continues to haunt our imagination.

