The reason you may not have heard of her is that Roberts writes what she refers to cryptically as "the big R". Romance.
All genres are scorned by literary types, but none more so than romance. In lit-land, it's lower than crime, lower than horror, lower, even, than sci-fi. But then, it's a genre written by women for women. Unless "a guy writes one and they call it something else," says Roberts. "[Then] it gets reviewed and made into a movie."
She doesn't actually say the words "David Nicholls" or "One Day" but they hover in the air. One Day was a breakthrough romantic novel, taken seriously by publishers, given a non-chick-lit cover and treated as a worthy subject for reviews in broadsheet newspapers.
"A woman writes it and it's just one of those," she says. "I mean, how long are you going to fight that battle?" Quite a while would seem to be the short answer.
Later, at the bookshop in Boonsboro, the small town in rural Maryland where she lives, she's doing a signing, answering questions and is phlegmatic.
What does she find helps keep her going when she's writing? "Alcoholic beverages." Does she tweet? "I'd rather stab myself in the eye with a flaming stick." What does she think of the recent news story claiming that romantic fiction gives women unrealistic expectations?
"Because women aren't supposed to have expectations, right? We're pretty smart. I think we know the difference between reality and fiction. I don't think that people read Agatha Christie, and then think: I know, I'll go and murder someone."
It would be hard to find a writer as unprecious as Roberts. She's 61, of Irish-American stock and still lives in the same house she moved in to as a newlywed teenager, aged 19. This despite her considerable wealth (she earns an estimated US$60 million a year) and her phenomenal success: in 2007, Time magazine chose her as one of only two writers in its 100 most influential people in the world (the other was Cloud Atlas author David Mitchell); she has won 19 Rita awards from the Romance Writers of America, the association's highest accolade, as well as being inducted into its hall of fame; and she's spent more than 893 weeks on the New York Times best-seller list - roughly 16 years.
One of the few writers to come close to her for sales is J.D. Robb, the author of futuristic police procedurals. Except that J.D. Robb is Nora Roberts (her publishers, unable to keep up with her frenetic output, invented J.D. Robb to take up the slack). And in January this year she became the third author to sell more than one million books on Kindle (after Stieg Larsson and James Patterson).
At a time when publishers are struggling to sell books, Roberts is a rare runaway success story. And yet she's barely known in literary circles.
Despite the New York Times stats, she has been reviewed in the paper exactly once, although one of its journalists did once come to her house to interview her and then wrote of her decor: "Inside, the furnishings are grandmotherly, not in the sense of a grandmother who once half owned half of Maine but rather in the vein of one inclined to shop for things on television."
Roberts, however, is used to doing things her own way. She lives in the middle of nowhere and she couldn't care less what the world thinks of her.
There is, she says, "more than a streak of misogyny in the way romance is viewed. All some people see is the big R and dismiss it. But I've made my career on my own terms and that doesn't necessarily suit the likes of the New York Times book review.
"They don't see that as legitimate. But it's just so insulting towards millions of people. Why would you apologise for what you read for pleasure? Just think of the illiteracy rate. Every book read for pleasure should be celebrated. And novels that celebrate love, commitment, relationships, making relationships work, why isn't that something to be respected?"
But romance fiction has changed - and Roberts is one of the reasons why. In Chasing Fire (one of five novels she's published this year), the heroine is a typical Roberts character: a gung-ho female forest firefighter from Montana, called Rowan Tripp. If you've not had much contact with romance novels lately, you might not even immediately guess that Chasing Fire is one. Its cover depicts a small aeroplane flying over a forest lit up by fire, and has the words "international best-seller" emblazoned across the top. And Rowan Tripp doesn't do much simpering. She jumps out of aeroplanes and spend her days risking life and limb on distant mountain tops, and first attracts the interest of the male love interest, Gull Curry, when she beats up a drunk who's trying to harass her in a bar. ("Before Gull was halfway across the room she slammed her boot on the man's instep, her other one into the crotch he'd been so proud of, then knocked him on his ass with an uppercut as fine as Gull had ever seen.")
Back in the 1980s, when Roberts started writing, the Mills & Boon model still dominated the market. It was a world in which the drinks were strong and the men stronger. Or, as she tells it, "He was often a Greek tycoon; she was often orphaned and raised by an aunt. She's on her way to a new job, working for the richest man in the free world. In the airport, she's rushing through with her battered suitcase. She runs into this man and the suitcase falls open, revealing a pitiful wardrobe - it's all neat and well-mended but sad. And he calls her a clumsy fool and helps her stuff her clothes back in the suitcase and storms off, and the next day she goes into the offices of the richest man in the free world and who should be there but the man she ran into in the airport?"
Roberts started out writing "category romances", short novels featuring formulaic plots, but over time she stretched and expanded the genre, Americanised it (when she started writing, most romance novels sold in America were by British authors) and ended up changing it beyond all recognition.
Her heroines are unrecognisable from the old Mills & Boon doormats. They have jobs, often quirky, interesting ones. They're not that bothered about getting married.
And it's this that Meg Cabot, the author of the Princess Diaries novels, says is the cornerstone of Roberts' success. "Her heroes and heroines are so strong yet so flawed. They have these personal handicaps, and that's something that's made Nora's books so different to many written in the past, because the characters are so relatable."
Roberts was one of the writers who changed the genre, she says. "Her heroines all had jobs. She doesn't write historicals. They're searching for themselves, not someone else. These aren't women obsessed with getting married. They're totally kick-ass."
There's a touch of the romantic novel to Roberts' life, too. The daughter of an electrician father and a housewife mother, she grew up with four older brothers and got married straight out of school to her childhood sweetheart.
"My mother should have locked me up. But there was no telling me." She settled in Keedysville, a tiny town that makes Boonsboro, a couple of miles away, look like a metropolis, and had two sons almost immediately. She was never ambitious and had no desire to have a career, nor any inkling that she would one day be a writer.
"Although there was obviously something trying to get out," she says. "Before I started writing, you name the craft, I did it. I made my own bread. I made my own jam. I needlepointed. I crocheted. I sewed all my boys' clothes. I sewed my own clothes. I was looking for something. And it was writing. It fed something in me."
It wasn't until she was trapped in the house for a week during a snowstorm with two toddlers that she picked up a writing pad and wrote her first novel: a way, she says, of preserving her sanity. She sent it to the romance publishers Silhouette. It was turned down, but a year later she wrote her second, Irish Thoroughbred, which was accepted. The timing was fortuitous. Shortly afterwards, she divorced and became a single mother, and, as for J.K. Rowling, writing was her salvation. It enabled her to stay at home to look after her children and still be able to support them.
Creating feisty heroines was something that came naturally to her. "I was, like, I don't want to be the secretary, I want to be the boss. I didn't want to write the kind of story where the man treats the woman like shit for the entire book and in the last chapter he tells her, 'I treated you like shit because I love you'. That won't do for me. Or for a lot of other writers. I started to write the kind of stories that I wanted to read. It was very instinctive. You just wanted the heroines to be a bit feisty."
It's the feistiness that her readers love. I chat to Cheryl Hudson, a 27-year-old corporate assistant, outside the bookstore as she waits in line to get her new Nora Roberts book signed. "They just kick ass. They're so strong. And independent. I love the men, too, but it's the women I like the best. She never casts them in typical roles." The signing at the Turn the Page bookshop is an annual event, now in its 16th year, with readers coming from all over the country to line up patiently outside.
There's a big crowd of them from adwoff.com, the Nora Roberts internet message board. Roberts was an early adopter when it came to the internet, and the homepage of adwoff.com bears the quote that was the inspiration for the site's name, "A day without french fries". A reader had asked her for her views on french fries, and Roberts replied: "Barb, how can one live without french fries? Not well, I say. In fact, I've been known to say a day without french fries is like a day without an orgasm."
The site now has 8000 registered users, and the core members have become friends not just with one another, but also with Roberts. On the day after the signing, a crowd of 30 or so (including one man) have brunch with her; it's not unlike a family reunion.
Sue Noyes, who created the site, tells me the story of how it came about. "I was on an AOL board and I said that I needed a new author. And I said, 'convince me what I should read next'. And Nora came on and wrote, 'go and find a used book store, buy one of my novels and see if you like it. And if you don't, you won't have wasted a lot of money.' And that impressed me. She's just an everyday sort of lady. She doesn't talk down to us. She's consoled us at times, and we've consoled her. There's a genuine give and take."
Roberts is an everyday sort of woman. It seems remarkable that she still lives in the same house as she always has (though it's been extended over the years). In her books, community and relationships are central, and that's true in her life, too. The Turn the Page bookshop is run by her second husband, Bruce. (He's a carpenter - they met when he came to put up some shelves for her.) Her son, Dan, runs the Vesta pizzeria a couple of doors down. She's also opened a bakery and a craft shop to support local artists. She recently renovated an old building across the street and made it into an upmarket B&B (which now features in a series of its own, the Inn at Boonsboro trilogy. The recently published first title, The Next Always, is already a best-seller).
Roberts is the undisputed queen of Boonsboro, but she's nothing if not loyal. She's still with the same agent she had at the beginning of her career - she's known her publicist, Laura, for 30 years; and Suzanne, her innkeeper, was a reader she met on the message board.
It's her work ethic that really defines Roberts. "Whatever I'm doing, I get very guilty if I don't put a good day's work in. I'm not one for making excuses. I had this Catholic upbringing. I was taught to finish what you start." She writes pretty much all day, every day.
"I had the blood and fire rule when my boys were young," she says. "You know, unless it's blood or fire, don't bother me."
Most importantly, she writes what she likes to read. And what's so bad about a happy ending, she asks?
"Romance gets disparaged for the happy endings. But all genres have expectations and all genres require narrative resolution. But it's disparaged because it's happy. And if it was important, it would be tragic. Which is bullshit. Look at Much Ado About Nothing - everybody is happy."
Does she prefer Shakespeare's comedies?
"Yes! It's a brilliant romantic comedy. It's one of my favourites. There's nothing wrong with being happy."
There isn't. Whatever the New York Times book reviewers happen to think.
The Next Always by Nora Roberts (Piatkus $29.99) and Betrayal in Death by J.D. Robb ($27.99) are both out now.
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