Karen Ferns, managing director of Random House NZ, sits in her Glenfield office and smiles so widely I can feel it down the phone. "Yes, it's been massive for us," she says. "We've sold 2000 copies in the last four months and every month we're selling more. That's big for this market."
Especially when 31 million English-speakers have already bought the thick, grey paperback (or the e-book) sporting a silver-grey knotted tie on the cover and a relatively ladylike tale of love, sex, bondage and discipline inside. The film rights have just been sold for US$6.2 million ($7.8 million), which means there's more, much more, to come.
We are talking about the Fifty Shades Of Grey trilogy, the worldwide publishing phenomenon which started as a "fan fiction" offshoot of the Twilight series of young adult vampire romances and spread like massage oil through social networking sites. The titillating, seriously sexy book masquerading as a love story rapidly turned into a breakaway best-seller. And within weeks of publishing, it became the fastest-selling trilogy of all time, surpassing even the Harry Potter series.
"Author E.L. James was just putting the story out there on the internet to fans," explains Ferns. But when her storyline was criticised for its highly sexual content, James took it off the fan fiction website and on to her own site. Titled Master Of The Universe, it was huge, containing all three volumes in the trilogy.
The book was picked up by a small Australian publisher, The Writers Coffee Shop, renamed and sliced into its three current volumes: Fifty Shades Of Grey, Fifty Shades Darker and Fifty Shades Freed. The big publishing houses started circling and Ferns' parent company, Random House UK bought the rights for US$1.2 million.
By then the series was on a roll. "You get to a tipping point and numbers start to roll," says Ferns. "Then the media stories appeared and a whole new thing kicked in. Something extra happened in Australia, and then New Zealand. There was an ingredient the media enjoyed. Radio especially did fun things with it and the public get to hear about it.
"When your staff come back saying, 'my hairdresser's talking about it', you know it's going to be big. And," says Ferns, "your life changes overnight."
Unlike other so-called erotic books, Fifty Shades Of Grey has a massively wide appeal. Men read it - at least some of it. Women of all ages love it.
"There was the bookshop assistant whose husband sent her flowers at work tied with a shiny grey ribbon and a note, 'looking forward to the weekend, signed, 'Mr Grey'," says Ferns. "It shows that this book is helping couples have more fun and taking a lot of us past our normal sexual practices in a nice, safe way."
True-ish. Anastasia Steele, the heroine of Fifty Shades, started out as what the nuns at my convent would have called a "pure" girl. She'd never had a boyfriend, never even had sex when she met the handsome, rich, mostly kind and scarily dominating Christian Grey. And somehow her innocence and surprise at the things he wants to do to her pulls the book back from being sordid and depressing.
While the writing is dreadfully repetitive and wooden, James does an excellent job of what rival publisher, Kevin Chapman of Hachette New Zealand calls "pulling the audience through the book". Indeed, anyone who manages to pull 31 million readers through an entire trilogy on a classic "boy-meets-girl" wafer-thin storyline by using timing, suspense and explicit sex with a sprinkling of bondage and discipline thrown in, means, on one level at least, she's a damned fine writer.
Having said that, not one reader I spoke to - and there were many - thought this was great literature (or was willing to talk on the record). No one wanted their photo taken. Some took umbrage and refused to discuss it. Others confessed to reading it on Kindle (where it's apparently the best-selling book of all time) so no one would know.
A 40-year-old was horrified when I asked her about it. "The girl at Paper Plus told me it was a love story. I've read two, despite the fact that it's terrible, so badly written. I'm so ashamed, but I couldn't put it down. I wanted to find out what happens, want to learn about his terrible childhood ... but I refuse to buy the third book."
A Parnell matron was "rubbished" by her former private school friends for just wanting to talk about it. "We all went out the other night and I mentioned Fifty Shades. They're all Remuera ladies. Only one had read it. She said it was garbage. The others just rubbished me. They said it was appalling the book was getting all this press time."
A sophisticated and wide-ranging reader, she had just finished The Rain Tree by Mirabel Osler, ("a dense and poetic memoir" published by upmarket Bloomsbury) and is adamant she enjoyed Fifty Shades of Grey just as much. "I've just ordered the next two books. I think one has to read all sorts of books to know what's bad writing, and I don't think Fifty Shades is bad at all. It might have made me feel hot and sweaty at times, but it didn't make me feel grubby."
The thing that upset her most, she says, is that her old friends were not even willing to discuss it. "I love questioning things. And I do have an open mind. What's more, we all have daughters who are learning from books like Fifty Shades."
A businesswoman heard about Fifty Shades on a trip to Hong Kong and Shanghai in early May, where it was beginning its phenomenal roll, and bought the first volume. "I like to have a look at things people are talking about," she says. "I don't like the domination and sub stuff, but the sex scenes are quite erotic. It's got pace and it's not normal chick lit."
"It doesn't pretend to be great literature. Actually, I can't put my finger on why it's so good."
Although she shared her e-books with her sisters and mother, a high school teacher was horrified when a mother brought the book to parent-teacher interviews. "I'm surprised by how many people admit to having read it." One of her friends is using it to help her get pregnant: "She'd left her boyfriend with strict instructions to read it while she was away at a conference."
So what makes a relatively ordinary book pole-vault to such heights?
Certainly not the highbrow critics. Fifty Shades Of Grey is widely described as "Mummy porn." The Telegraph critic called it "treacly cliche, while the Chicago Tribune described it as "sprinkled liberally and repeatedly with asinine phrases".
Author "E.L. James", who came out using her real name, Erika Leonard, when she realised her book was a hit, can't explain it. Even Ferns is unsure about why people are so entranced. "The front-runner [in a craze like this] is always different," she says.
"But I'm not exactly sure what the mix is that's made it so popular. The freshness of the plot certainly works. The central male character is interesting - she's saving him from an abusive childhood - so it's not as predictable as some people think. It's a love story at heart, which gives people permission to look at it quite broadly."
"Personally, I think it's escapism and romance and it offers a bit of guilty pleasure because of the erotism wrapped around it. All sorts of people respond to it. There's also an educational factor."
Booksellers' feedback is interesting: "I'm 40 and there's stuff I didn't know that I found out from this book," says one. An 84-year-old, buying books for the library of her old people's home, took it up to the counter and, when the bookseller raised her eyebrows, put her hands on her hips and said: 'I'm 84, I've got four children and I want to buy this book!"'
"These sorts of anecdotes say something about our society - that this book's acceptable; it's moved into the community in a really big way," says Ferns.
"As publishers, we'd love to know how these phenomena happen," says Hachette's Chapman.
"Then we could influence it."
Chapman, who worked in North America selling romance and erotic romance in the early 90s, insists that there is nothing new about Fifty Shades. Except the fact that everyone's reading it.
"All the conceptions about these books are that they're about erotica," he says. "But these are romance novels. We used to put chillies on our catalogues to indicate how spicy the books were. Five chillies meant extra spicy, no chillies at all meant that you never got past the bedroom door."
By those criteria, Fifty Shades is probably a two. "I think all this talk about a surge in erotica fiction misses the point," Chapman continues. "If your book's not essentially romance, you're going to miss the market."
"What's new is that the Fifty Shades trilogy is packaged as mainstream fiction," says Chapman, "and it simply broke out and became socially acceptable."
Not that he's complaining. Indeed, Hachette is about to release its own erotic novel, Eighty Days Yellow, by New Zealand writer Vina Jackson. And that's definitely 3-plus on the chilli scale.
Random House's publishing rival, Penguin, also has a copycat book. Called Bared To You, it has a similar style and plot and started as an e-book. "Like many other publishers, we're jumping on the bandwagon," admits Penguin New Zealand's sales manager, Carrie Welch, with refreshing candour. "Bared To You was a rushed book. Now it's number four on the New York Times best-seller list and it's been there four weeks.
"The local edition came out yesterday and after one day's trading has already appeared on local best-seller figures.
How can that be? "We're not sure, but it's a good sign. It's not in the top 10 but it's on the list. And we're on to our second printing."
Meanwhile established American writer Sylvia Day is presumably tapping away furiously. The two other novels in her Crossfire trilogy are due out in September/October and November (well in time for Christmas).
The money to be made is obviously huge. As Ferns explains, the determining factor for a publishing phenomenon is that it brings a healthy chunk of new readers into the market. Fifty Shades started with thousands of online readers and spread through the social media. "Readers talked about it with their friends on Facebook and the other social networking sites. "That's what brings the numbers up."
The Harry Potter series, The Hunger Games and the Twilight series of 2009 all brought new young readers into the market and once they were established on the best-seller lists, the books often sold as bundles. Similarly, all three Fifty Shades novels are currently on special for $50 at Whitcoulls. Not much of a margin, but when you're selling thousands of copies it adds up. The Wall Street Journal reported on July 10 that US sales of nearly 20 million had brought in US$145 million for publisher Vintage.
More importantly, says Penguin's Carrie Welch, we can stop worrying about e-books snatching the heart out of print. "With this book it's completely the opposite. The e-book's generated a demand for the real book. It debunks the theory that e-books are going to be the demise of the hard cover."
So what happens next? How big will Fifty Shades become? Surely readers will soon tire of Anastasia Steele and Christian Grey and their steaming hot sex life?
According to Ferns, this is just the beginning.
"We believe it'll go past Christmas. There will be a movie and lots of discussion with that. It'll fuel interest when they announce who has got the two leading parts. And when the movie comes out next year, it'll fire up again.
"Each of these publishing phenomenons takes its own course. With the Twilight series the movies kept it going well over two years. But this is bigger. This book will be talked about for some time," she says, and I can feel that smile building again. "It's large, large numbers."
Have you read Fifty Shades? What did you think? Why do you think the trilogy is so popular?