IT IS the book with arguably the most famous opening line in literature . . .

"Last night I dreamt I went to Manderlay again." When the novel Rebecca first appeared in l938, it was promoted as "an exquisite romance" by publishers Gollancz . . . much to the frustration, not to mention surprise, of the book's author, Daphne du Maurier. She had feared the novel "too gloomy"' with an ending "too grim"' to have mass appeal, while its dismissal as "women's fiction" was a source of irritation.

True, the story has all the hallmarks of a classic romance with more than a hint of the gothic: a young, innocent bride competing for the love of a domineering, older man against the real or imagined spirit of his first wife. The ever-present spirit of the dead Rebecca, who we never see or hear, dominates almost every page. Often compared to Charlotte Bronte's Jane Eyre, du Maurier's story can be read on one level as a romance. But there are darker forces simmering below the surface. Dreams turn into living nightmares.

There is a sense of foreboding in both novels, emanating from the eerie wing of the gothic mansion where the drama takes place.

The author of Rebecca described this drama as "psychologicalf and rather macabre". Jealousy, class prejudice, suggestions of bisexual lust and lesbian obsession, murder, the supernatural and a tangible sense of atmosphere all serve to make Rebecca disturbing and compelling.

Du Maurier took great risks with her story. And she is very clever in leading the unwitting reader to form an unholy empathy with the nameless narrator, the second Mrs de Winter.

This timid, pallid woman seeks validation for her very existence in the love of her husband. When Maxim de Winter confesses to her that he murdered his first wife Rebecca (who was possibly pregnant) and then made it look like a sailing accident, she meets this shocking admission only with a sense of relief: Max never loved Rebecca. He loves her and that is all that matters. She is an accessory after the fact, and so too is the sympathetic reader.

When he came to film the novel in 1940, director Alfred Hitchcock made a significant alteration: there is no murder in the cinematic version. Rebecca dies, but accidentally. Perhaps reluctant to offend the strict moral code of the time in this, his first Hollywood picture, it seems even the "master of the macabre" found du Maurier's scenario of complicity with a murderer unacceptable.

Du Maurier's fascination with the darker side of human relationships is among the subjects of debate in a series of documentaries, debates and dramas celebrating the centenary of her birth. Serialisations of her books and short stories will feature on BBC Radio 4. One of the major literary events will be the annual Daphne du Maurier festival in Fowey, Cornwall, which this centenary year will feature a talk with the author's children.

Helen Taylor has edited the Daphne du Maurier Companion, a definitive guide to the author's life and work with contributions from leading writers including du Maurier's biographer Margaret Forster. Currently Professor of English at the University of Exeter, Taylor has lectured extensively on women's writing and popular culture. As a teenager, she admits she was dismissive of Rebecca, believing it to be just another love story.

"I only wanted to read 'intelligent' books. Then, when in my early 20s, I secretly read Rebecca as a romance, " she says. "Like so many readers, I fell in love with Max de Winter and this romantic notion of living in a huge house by the sea with lots of servants.

But Rebecca, and novels such as Jane Eyre, beg the question as to why romance is so important to women . . .

including feminists? The subtext of Rebecca is actually about the terrible compromises women make in marriage, about how women deal with violence and jealousy. The book shows the skill of du Maurier in creating that climate and atmosphere. How well she sows seeds of doubt in her narrator: we feel that jittery sense of 'am I safe in this house?'" The model for Manderlay was a deserted house in du Maurier's beloved Cornwall.

Menabilly, an imposing grey stone mansion on an isolated headland near Fowey, fascinated her. Four years after the publication of Rebecca, she bought a long lease on the property and raised her three children in the chilly, forbidding house.

Although not stated in the book, Cornwall is the undisputed setting for Rebecca, with its wild landscape emblematic of the passion and the encroaching sea offering a sense of menace and danger. That famous first chapter . . . initially written as the epilogue but then ingeniously placed at the very beginning . . . eerily captures the narrator's dream of noiselessly moving up the overgrown drive and suddenly coming upon the silent, ghostly shell of the house.

If Manderlay is based on her home, then the two leading female characters in Rebecca are believed to be a composite of the dual personality of its author. Du Maurier's daughter Flavia has said: "Both Rebecca and the second Mrs de Winter are based on my mother: the dark side is Rebecca, while the young Mrs de Winter represents her timidity and social awkwardness."

There is a third female in the book. Mrs Danvers, the malevolent housekeeper at Manderlay, guards the memory of her dead mistress with a chill obsessive passion way beyond the call of duty. There is an implied lesbian attraction inherent in that obsession, while bisexual affairs are suggested as being part of Rebecca's alleged "promiscuousness".

As a schoolgirl, the young Daphne invented a male alter-ego. As a young woman, she was happiest sailing and messing about in boats off the Cornish coast . . .

in her favourite garb of men's shirts and trousers. So far, so Katharine Hepburn. But it was her affair with actress Gertrude Lawrence and an unrequited passion for Ellen Doubleday, the wife of her US publisher . . . both revealed in Margaret Forster's biography . . . that lend credence to the suggestion by her daughter Flavia that du Maurier was "muddled about her sexuality". Du Maurier used the word "Venetian" as code for "lesbian". But there was nothing Venetian about her marriage to Frederick Browning, an officer in the Grenadier Guards with whom she had three children. She was pregnant with her second child when writing Rebecca.

The ambiguous elements in all of her work have invited endless speculation and interpretation of the woman's own character. She had contradictory traits, firmly believing in a conventional marriage and yet one within which there were infidelities on both sides.

Irish writer Orna Ross . . .

whose first novel, Lovers Hollow, centres on dark events during the Civil War . . . beieves du Maurier's writing remains relevant to 21stcentury readers, particularly women.

"The two Mrs de Winters give us an extreme picture of the opposite poles of female gender roles . . . 'stand by your man' good girl on one side, sexually liberated bad girl on the other. Most women still face some version of this question in their lives. The social emphasis in 1938 would have leaned more in the direction of dutiful wife, but finding your own place on that spectrum . . . a place where your own needs remain central to your own experience . . . is as difficult for an individual woman to negotiate today as it ever was. I think men are less likely to identify with the subterranean anxieties, passions and dilemmas that underwrite all of du Maurier's work. That is why writers like her, whose interest is the female experience, are so often trivialised and dismissed."

"Du Maurier is mistress of the grey area, " according to Ross. And within that grey area also lurks the supernatural element to her writing that holds such a morbid fascination for readers. Many thriller writers, notably Stephen King, have been influenced by her.

Her disturbing short stories, written many years after Rebecca, and which subsequently inspired two spine-chilling films . . . Hitchcock's The Birds (1961) and Nicholas Roeg's Don't Look Now (1973) . . . suggest something of inner turmoil. Du Maurier said as much in a letter to a friend: "In a sense, they are all a protest at the cruelty and misunderstanding which abounds in the world . . .

beneath the surface lurk evils we do not understand, things in ourselves."

'The Daphne du Maurier Companion', edited by Helen Taylor, is published this month by Virago