I still feel worn out,' says Kate Pullinger, three months after finishing her new book.

No wonder: Pullinger had just seven days to complete the first draft, writing 14 or 15 hours a day, 10,000 words a day, breaking off every few hours to have a soothing bath. She then had a mere five weeks to smooth the rough edges. The reason? The book, a novelisation of Jane Campion's film The Piano, had to be finished in time for the Oscars.

The Piano - a love story set in Victorian New Zealand - has been the art house blockbuster of the season, sister to the BBC adaptation of Middlemarch and the Picasso exhibition at the Tate.

Last year, the film shared the Palme d'Or at the Cannes Film Festival; this year it was nominated for eight Oscars and won three. In the United States, it has grossed nearly dollars 40m; the New Yorker magazine has devoted almost as many cartoons to the film as it has to the Bobbitt case.

In the UK, the Piano has taken more than pounds 4m. A Q & A session on 'Piano mysteries' became a regular feature of our sister paper, The Independent on Sunday. If Baines (played by Harvey Keitel) couldn't read, why did Ada (Holly Hunter) declare her love for him by sending a message written on a piano key? How did Stewart (Sam Neill) manage to sever just one of Ada's fingers with such a big axe? And why didn't she put a piece of felt on the end of her tin finger to stop it tapping when she played the piano?

Theoretically, Piano obsessives will rush out and buy the book. On the other hand, snobbery may win the day: novelisations are commonplace for schlocky studio films, but the chattering classes prefer it the other way round - movies based on novels. Though the front cover is upmarket and understated, how will readers feel about the back? 'The explosive and sensual story of a Victorian woman's sexual awakening,' whispers the blurb, huskily.

'People are very quick to sneer,' counters the book's publisher, Liz Calder, who also published the screenplay of The Piano. 'But I don't care what they say. I adored the film. Why not want more of something that you really love? Too much of good thing can be wonderful.'

Originally, the novel was to have been written by Jane Campion, whose fiction has been published by Bloomsbury. After two chapters, however, prior film commitments (an adaption of Henry James's Portrait of a Lady) took precedence. At the suggestion of Calder, Campion handed over to Kate Pullinger, who was young, talented and available. Pullinger had one meeting with Campion before the film's release last October, and then went solo, locked up in her first floor flat in north London. Her only aids were a computer and a video of The Piano, which she watched in 30-second sections and then wrote about, fitting in background material as appropriate. 'I must have seen it 995 times,' she says, with feeling.

Her only interruptions were film company motorbike messengers, bearing background material from the British Museum, on everything from bonnets to whales. Pullinger barely saw her husband, the theatre producer Simon Mellor, who was working even longer hours on a new play.

Even her dreams were filled with The Piano: not pursuit by an axe- wielding Campion but the exhaustingly prosaic - looking up words in the dictionary. 'In my moments of extreme madness,' says Pullinger, 'I imagined my alternative, post-modern version of events, The Anti-Piano.' Sample passage: ' 'George Baines drew Ada towards him. He fell on to his knees and lifted her skirt and its heavy crinoline cage and buried his head' . . . this is the bit where we get to see Harvey's amazing square body butt- naked again.'

The principal challenge was not creating an unsympathetic female heroine (a feature of Pullinger's last book, Where Does Kissing End?) but recreating the film's rich visual texture. Another was the 'big sex scene' between Ada and Baines.

'It was difficult,' says Pullinger, 'because of the constraints of the period - trying to figure out what kind of language to use and how explicit to be. The sex that I'd written before was very explicit and graphic, with lots of four-letter words - not suitable.' Also tricky: imagining Baines without Keitel as the blood-spattered star of Reservoir Dogs getting in the way.

And the finished product (revised by Jane Campion, who is credited as co-writer)? 'I wouldn't call it great literature,' says Liz Calder, 'but I thought it was very good - extremely well written and obviously of special interest to people who were intrigued by the film. We hope to sell 20,000 to 30,000 copies.'

Sadly, there are no answers to the burning questions posed in the Independent on Sunday. But the Big One - why did Ada stop speaking? - is answered in full. Piano- obsessives should turn at once to page 17 and look for the phrase 'sugar dispenser'. . .

Pullinger can't bear to read the book - at least not yet. But as a reward for her sufferings, on completion of the book, she treated herself to a week in New York, 'visiting friends, going to art galleries and drinking'. As for her fee (which she won't reveal), she managed to negotiate a 'tiny, tiny percentage of the American royalty' which should make a nice nest egg.

And you never know, maybe the high-speed training will pay off. Her new novel, Between - coincidentally about Victorian settlers in the Commonwealth - has been rumbling along for two years. She hopes to finish it by the summer.

'The Piano' is published by Bloomsbury on 21 April, pounds 5.99.

(Photograph omitted)