A graphic erotic novel by an obscure writer is a hit with women.

Fifty Shades of Grey, an erotic novel by an obscure author that has been described as "Mommy porn" and "Twilight" for grown-ups, has electrified women across the US, who have spread the word like gospel on Facebook pages, at school functions and in spin classes. Or as the handwritten tag on a paperback copy in a New Jersey bookstore helpfully noted, "Yes, this is THE book everyone is talking about. "

The problem has been finding it. The first book of a trilogy, it was published by a tiny independent press in Australia, and distribution in print has been limited and sluggish, leaving bookstores deprived of copies. The lion's share of total sales (more than 250, 000 copies for all three books) has come from ever-discreet e-book downloads, which have propelled Fifty Shades of Grey to No. 1 on the New York Times e-book fiction bestseller and No. 3 position on Amazon's bestseller list.

Now American publishers have just concluded a battle over the rights to rerelease the book in the blockbuster fashion they think it deserves. Vintage Books, known for its highbrow literary credentials, has won a bidding war for the rights to all three books, paying a seven-figure sum. This week, the publisher released new e-book editions of the trilogy. Weeks later will come a 750, 000-copy print run of redesigned paperback editions.

"We're making a statement that this is bigger than one genre, " said Anne Messitte, the publisher of Vintage Anchor. "The people who are reading this are not only people who read romance. It's gone much broader than that. "

Fifty Shades of Grey and the two other titles in the series were written by a British author named E L James, a former television executive who began the trilogy by posting fan fiction online. The books, which were released in the last year, centre on the lives (and affection for whips, chains and handcuffs) of Christian Grey, a rich, handsome tycoon, and Anastasia Steele, an innocent college student, who enter into a dominant-submissive relationship. The narrative is built on the purple prose typical of pulp novels, with lines like, "My inner goddess is doing the dance of the seven veils. "

Publishing executives said the word-of-mouth excitement accompanying Fifty Shades of Grey was reminiscent of that accompanying novels like The Da Vinci Code, The Kite Runner and Eat, Pray, Love.

Except this book has been credited with something else: introducing women who usually read run-of-the-mill literary or commercial fiction to graphic, heavy-breathing erotica. And in the cities and suburbs of New York, Denver and Minneapolis, the women who have devoured the books say they are feeling the happy effects at home. "It's relighting a fire under a lot of marriages, " said Lyss Stern, the founder of Diva-Moms. com and one of the early fans of the series. "I think it makes you feel sexy again, reading the books. "

One woman, who insisted on anonymity so that she would not embarrass her employer, said the book had gained an obsessive following among her friends, the first erotic novel they have ever discussed. "Women just feel like it's OK to read it, " she said. "It's taboo for women to admit that they watch pornography, but for some reason it's OK to admit that they're reading this book. "

The trilogy has its detractors. Commentators have shredded the books for their explicit violence and antiquated treatment of women, made especially clear in the character of Anastasia, an awkward naif who consents to being stalked, slapped and whipped with a leather riding crop.

"What I found fascinating is that there are all these supermotivated, smart, educated women saying this was like the greatest thing they've ever read, " said Meg Lazarus, a 38-year-old former lawyer, whose friends and acquaintances have been buzzing about the book. "I don't get it. There's a lot of violence, and this guy is abhorrent sometimes. " Online reviewers have criticised the author for her plodding prose and habit of printing lengthy contracts and e-mail exchanges between characters in the text.
"The books are just so long, " said Sarah Wendell, a blogger and the co-author of Beyond Heaving Bosoms. "They suffer from the same lack of content and pacing. They're very dense, with a lot of detail. They just don't go anywhere. " But executives at Vintage say they believe that sales of the series so far are just the tip of the iceberg.

Conversation about the book online has fed many of the sales, said Patricia Bostelman, vice president for marketing at Barnes & Noble. "I think this shows very clearly what the blog network can do, " she said. "The word-of-mouth so thoroughly outpaced the availability. "

James's agent, Valerie Hoskins of London, is fielding offers from Hollywood producers for the film rights and from foreign publishers for the rights to the book in other languages. "I think it can only get bigger in terms of its success, " Hoskins said. "One of the things about this is that in the 21st century, women have the ability to read this kind of material without anybody knowing what they're reading, because they can read them on their iPads and Kindles. "