A Hidden Struggle : DAPHNE DU MAURIER: The Secret Life of the Renowned Storyteller, <i> By Margaret Forster (Doubleday: $25; 457 pp.)</i>

In recent years, biography as a genre has been callously transformed. We have come to recognize its unwillingness to leave any page unturned in a life: no place remains private: we must be privy to every transgression of the learned, the talented or famous, no matter what--alcoholism, marital violence, perverse sexual proclivities.

Readers will lap up such intelligence, whether it be Freud’s cocaine addiction, Jack Kennedy’s lust for actresses or Laurence Olivier’s fling with Danny Kaye. Yet we might well question what such intimate revelations really add up to in recounting the life of a politician, an athlete, or actor, scientist, artist? Do they, we wonder, contribute anything to an understanding of their achievement?

Still, when it comes to certain novelists, it sometimes is evident that intimate, even scandalous, disclosures help to elucidate their work, often introducing a fascinating subtext to their fiction. Deep traumas or obsessions may fill in previously puzzling blanks, determine the power of haunting themes, explain the excessive, unintelligible venom of certain characters, adding a new dimension to their artistry.

This was the case, for example, with a biography of Margaret Mitchell published several years ago. The author of “Gone With the Wind” was revealed to have been date-raped in her belle, courting days by a man vaguely identified as “Brett.” It was an experience Mitchell herself never to acknowledged publicly in her lifetime. Yet the disclosure, for this reader certainly, explained the immense force of her heroine’s love-hate attachment to Rhett Butler. It made clear why it had always seemed the most thrilling feature of Mitchell’s rather object, almost mindless portrait of a stereotypically flirtatious Southern belle, Scarlett O’ Hara. Another striking example of the hidden power of a secret eroticism was the R.L.B. Lewis’ revelations of Edith Wharton’s unknown erotic life.

The same might be said now for the new Margaret Forster depiction of the “secret life of the renowned storyteller,” that unkillably popular British novelist, Daphne du Maurier.

With materials drawn from previously unknown diaries and letters, Forster has been able to let us see a side of Du Maurier until now closeted away, exposing a whole other emotional dimension to her fiction’s compelling fascination.

Though the author was ever “a chameleon” to her own children, who learned of her bisexuality through these distressing new documents (only upon completion of this biography), Daphne du Maurier herself was never in doubt of her own nature. From the first, she liked to think of herself as a boy. But reflecting the prejudices of her generation, she greeted with fury any suggestion of Lesbianism. She did not, would not, see herself as homosexual.

But for her readers, how important Forster’s revelation is! It shines a new light on aspects of Du Maurier that seemed mysterious and unfathomable. In the early pages of “Rebecca,” for instance, we come upon her nameless narrator’s own view of herself in relation to the dashing Maxim De Winter “I was like a little scrubby schoolboy (!) with a passion for a sixth-form perfect. . . .” Or, a little later, note her narrator’s puzzling statement upon being asked to marry him, “You don’t understand,” . . . “I’m not the sort of person men marry.”

Add to that the passionate attachment of Mrs. Danver to the dead Rebecca (an echo of Daphne’s earliest affair with her French governess, Ferdy, a woman she continues to correspond with, and remained loyal to all her life). And then, the presentation of Mrs. Danvers, the eerie “skull’s face, parchment white, set on a skeleton’s frame,” her vengeful stance toward Rebecca’s replacement, bringing immediate foreboding and terror to the awkward, young (and ostensibly heterosexual) new wife.

And when we learn from Forster the whole picture, of du Maurier’s strong attachment to, and curious identification with, her father, see her reserved, indifferent, cold mother, discover her struggle to contain her sexual attraction to women from childhood (what she calls Venetian tendencies), and add to it all her later determination to shut away one of her selves forever, we understand the dark shadows in her work: the guilt, the terror, the unease, even the namelessness, of her narrator.

With Daphne du Maurier’s marriage to Major F.A.M. “Tommy” Browning, British war hero, and later a valued staff member in the royal household, she determined to lock away forever one of her two personae. It was her troublesome “boy” self she had decided must finally be kept “in the box”--a box never to be opened again.

She was born in 1907 to a talented upper-class family. Du Maurier’s father Gerald was a well-known actor and stage manager; her grandfather George was a celebrated artist as well as an acclaimed novelist (“Trilby,” “Peter Ibbetson”). Daphne was the second of three sisters who grew up in a sophisticated, privileged London Atmosphere.

Yet her own childish fears could only have been exacerbated by her father’s obsesion with having failed to produce a male heir. He wrote in a poem to her his lament that she, “who seems to live in Kingdoms all her own” could “do deeds of daring and much fame,” “if only she had been born a boy.”

Her won writing talents emerged early. They were to become more than an escape, her very salvation. But even later, when she had securely buried one part of her secret self she insisted that it was only her “No.2” self, that, “boy in the box,” who fired her creative powers. Writing made life possible and gave her “release from thoughts images and ideas which disturbed her,” observes Forster.

Unfortunately there was no denying her physical self. In what she herself felt a compulsion, No. 2 emerged in midlife. First, there was her attraction to Ellen Doubleday, the beautiful, urban wife of her American publisher. Daphne pursued Ellen passionately: yet her love remained unrequited, and she suffered from her rebuff. It was than that she found in the actress Gertrude Lawrence the love and sexual realization she desired. The actress’ early death nearly destroyed the writer altogether.

Margaret Forster’s admirable biography has not only succeeded evoking a life’s secret struggle, but contributes to our understanding of the hypnotic appeal of du Maurier’s fiction.