Too Big : The woman behind the image : GARBO: A Biography, <i> By Barry Paris (Alfred A. Knopf: $35; 512 pp.)</i>

When a shy 16-year-old Swedish shop girl named Greta Lovisa Gustafson made her motion picture debut in a short promotional film called “How Not to Dress,” one of her co-stars was less than pleased. “You’re not going to have that fat girl in the picture, are you?” he tactlessly complained. “She won’t fit the screen!”

In fact, once she changed her name, emigrated to Hollywood, and chipped away at the baby fat, that awkward actress became too big for the screen in ways no one had anticipated. As Greta Garbo, her every action became epochal, worthy of mile-high headlines. “Garbo Talks.” “Garbo Laughs.” “Garbo Wants to Be Alone.” In an era that was movie-mad and star-crazy to an extent that is hard to credit today, Garbo outdid them all, becoming, in one historian’s typically awed assessment, “only the greatest who ever was or ever will be on screen.”

Her indescribable face was at the heart of her success, a visage that invariably drew gasps when it began to appear in public. “Such a face you see once in a century,” said G. W. Pabst, who directed her in “The Joyless Street,” while critic Kenneth Tynan called it “the furthest stage to which the human face could progress, the nth degree of cultured refinement, complexity, mystery and strength.”

Striking in person, Garbo was extraordinary on celluloid, finding in films like “Queen Christina,” “Camille” and “Ninotchka” a way to exquisitely magnify both her beauty and its effect. Clarence Brown, who directed her seven times, was continually impressed by her ability to make you “see thought,” the normally acerbic Billy Wilder believed that “she became all women on screen, the miracle happened in that film emulsion,” and even as cold-blooded and competitive an observer as Bette Davis called her “pure witchcraft. I cannot analyze this woman’s acting. I only know that no one else so effectively worked in front of a camera.”

But, as Truman Capote shrewdly guessed, it was in no way easy to live behind the face of the century, so much so that “Garbo herself must have come to regret the rather tragic responsibility of owning it.” Timid, insecure, painfully reserved, with a strong need for solitude that well predated her movie experience, Garbo fled in horror from the consequences of having her youthful dreams of triumph fulfilled. “Success acted on Garbo like a depressant,” film critic Alexander Walker wrote, and though she didn’t plan on it, her failure to make a film after the unsuccessful “Two-Faced Woman” in her 36th year is hardly a surprise.

Ironically, Garbo’s almost pathological reticence seemed to exacerbate the public’s determination to discover what she was really like. Though the actress granted barely more than a dozen interviews during her lifetime, that lack of access didn’t halt the flow of printed material; some two dozen books and thousands of stories all took a stab at penetrating to the essence of this enigmatic woman who died at age 84 in 1990.

Barry Paris, previously the author of a biography of Louise Brooks, is the latest to make the attempt and in many ways the most successful. He has done a prodigious amount of research, both in scouring already published memoirs and in gaining access to new material, such as a cache of letters between Garbo and her closest Hollywood friend Salka Viertel and some 100 hours of transcribed telephone conversations the actress had with Sam Green, an art dealer and companion of her later years.

As a result, if there is any fact to be discovered about Greta Garbo it can be found here, everything from the room numbers of hotels she frequented and the kind of jam she ate on a particular Italian holiday (lingonberry) to an examination of her tennis game (“fast, slashing”) and numerous paragraphs on what Paris insists is “the compelling subject of Garbo’s feet.”

Paris’ book also does a solid job of tracing the actress’s story through its by-now familiar paces, enthusiastically correcting misinformation whenever necessary. We see her beginnings in Sweden, her willing subjugation to the “loud, egotistical, and imperious” director Mauritz Stiller, her turning to Hollywood and subsequent triumphs in films both silent and sound.

What we don’t see is Garbo being happy, because she rarely was. “No one making films can be happy,” she categorically told one friend, and her temperament was so melancholy she called a woebegone dead tree outside the window of one of her homes “my one joy in Hollywood.”

In fact, say Paris, “Garbo’s ego boundaries and personal identity were never very strong. Hers was an empty-vessel syndrome common to many great actors: ‘Make me into what you will’ went the message, and directors did so. She was a textbook case of dazzling exterior far removed from inner self. . . . Garbo’s perception of helplessness explains much about her withdrawal and her life: She never understood that she could control things--except by withdrawing.”

This kind of “identity void” made Garbo gravitate toward tyrannical men like Stiller, who told her exactly what to do, or “the entertaining but emotionally immature kind” she could manipulate, such as the actor John Gilbert and, later, the photographer Cecil Beaton.

But most of all, despite her love-goddess image, Garbo was “a largely celibate narcissist,” who, in critic Parker Tyler’s apt phrase, “wanted to be where sex wasn’t.” After her passionate involvement with Gilbert, she tended in theory to prefer the company of women, but in practice, Paris says, “four years of research on two continents . . . unearthed qualified proof of a single Garbo sex affair, and provided circumstantial evidence for only three others.” No wonder a friend said: “She wasn’t a lesbian. She wasn’t anything .”

Paris is best in these areas of emotional analysis, and his detailing of the Howard Hughes-like extent of Garbo’s passion for staying hidden (“She would make a secret out of whether she had an egg for breakfast,” Beaton complained) makes intriguing reading. Two things, however, finally trip “Garbo” up, though both are to a certain extent unavoidable.

To have the stamina for this kind of formidable research on a single person, an author must be an enthusiast, but Paris tends to overdo it. His chatty style, with its reliance on superlatives and persistent employment of cliches, is more passionate and gushy than judicious, and his book is weaker for it.

More of a problem, and something Paris could do nothing about, is the hard fact that Greta Garbo, especially during her aimless last 50 years, was not a particularly interesting person. Self-centered, without a compelling inner life, she could fascinate for only so long before, as art historian James Pope-Hennessy noticed, “it gradually dawns on one that she is entirely uneducated, interested in theosophy, dieting and all other cranky subjects, has conversation so dull that you could scream.” Even the usually worshipful Cecil Beaton once admitted “if she hadn’t been ‘Garbo’ nobody would’ve wanted to be around her for ten minutes.” Her films were incandescent, but her life, as she knew better than anyone, held no magic to match what appeared on the screen.