Interview: Diana Gabaldon

THE setting couldn't be any more wrong.

A meeting with Diana Gabaldon, the best-selling author of the multi-million-selling Outlander novels should take place in a wind-swept, heather-strewn glen, surrounded by Scotland's ancient, majestic landscape. Or at least within sight of a cluster of standing stones. As it is, we're in an anonymous business hotel, all standard-issue furniture and frosted glass. What surrounds us is a city landscape painted in a palette of dirty white and slush grey. The squinty bridge is lost in smirr against the sleet-filled sky, and the Clyde looks like a smear of dirty water running towards a drain.

And yet, in a way, seeing the Arizona-based writer against this backdrop feels right. Gabaldon's enormously successful novels – Cross Stitch (1991), Dragonfly in Amber (1992), Voyager (1994), Drums of Autumn (1997), The Fiery Cross (2001), A Breath of Snow and Ashes (2004) and now An Echo in the Bone – are as couthy as a kailyard. Featuring an 18th-century Scot, Jamie Fraser, a perfectly imagined noble savage complete with wiry ginger hair on his chest and an unending supply of bravery, and his 20th-century lover, Claire Beauchamp Randall (it's time travel – don't worry, we'll get to that), Gabaldon's Scotland is a construct, a Brigadoon-like fabrication, albeit with impeccable historical detailing.

Sitting at a corner table tucked against ceiling-height windows, Gabaldon is striking, her long black hair poker-straight, her eyes bright, but the view is gritty reality. The poetic beauty of Loch Lomond and the Trossachs is only half an hour away, but the urban sprawl of Glasgow is a reminder of what Scotland really is, a million miles away from Gabaldon's literary confection, whipped up from guidebooks and historical texts, old paintings and photographs.

Gabaldon is a literary phenomenon. Self-taught and idiosyncratic, she spent her career as a scientist, not a fiction writer. For 12 years she was a professor at the Centre for Environmental Studies at Arizona State University. She worked on scientific computation (the use of computers in scientific research) and had a background in marine biology and animal behaviour. Her first novel was written "for practice", just to see if she could. If it sounds unusual, it fits perfectly with Gabaldon. She is fastidious, a lover of detail. Her novels number thousands of pages of densely packed prose, labyrinthine plotting, historical detail. She speaks in the same way that she writes, answering questions in long statements, leaving nothing out, dates, places, times. Gabaldon is a fan of specificity.

So it's interesting that the books came about almost accidentally. The central character was a Scot only because Gabaldon happened to see a Dr Who repeat featuring a man in a kilt as she conjured her character. She chose to fix him in the 18th century simply because being allowed to research the period meant she could avoid having to make the whole thing up. The time-travel element came about because the other main character, Claire, was resolutely modern when she appeared, apparently full-formed, from Gabaldon's imagination.

Be that as it may, the books have won a fiercely loyal fanbase, not least in Scotland. Gabaldon was a guest of honour at the Gathering last year, many make pilgrimages to visit locations that they believe might have featured, and the number of people learning Gaelic across the world has increased because of Gabaldon's use of the language in her novels. This says as much about Scotland's continuing role as a perfect backdrop for a certain kind of romantic imagination as it does about Gabaldon's way with words.

How funny then, that when she wrote the first novel, she had never even been here. "I was not intending to show the book to anyone so I couldn't very well tell my husband I was going to Scotland to do some research," she says in a small, scratchy voice. "I did it from library research. I was a university professor so I knew what to do with a library. That's why I decided to write historical fiction in the first place – it seemed easier to look things up rather than make them up, and if it had turned out that I had no imagination I could steal things from the historical record. So far so good."

You could say. Gabaldon has sold more than 18 million of her Outlander series alone. She has also launched another series, featuring one of the peripheral characters – Lord John Gray, a dashing gay soldier and statesman – and she shows no signs of stopping, beginning the three-year cycle of research and writing for the next novel as soon as promotional activities for the most recently published are complete.

But it hasn't all been straightforward. Gabaldon's novels are impossible to classify in terms of genre: replete with historical detail, they might be described as military history, and focused on the relationship between Jamie and Claire, there are elements of romance, including plenty of lusty sex. But then there's the time travel. Gabaldon's first editor had to threaten to quit to ensure that the three-book deal the writer had been offered was honoured. Gabaldon herself has had several skirmishes with editors and the book industry to have her work positioned on the general fiction shelves of bookshops rather than amongst the romance or fantasy. In one letter sent to an editor, she described the problem of her literary identity in typically Gabaldonian terms. "We seem to be in a certain difference of opinion regarding my literary identity. I think I am Alexandre Dumas with a time machine and you appear to think I am Dame Barbara Cartland in the large economy size."

She laughs when I quote this to her, evidently still pleased with herself. She makes no attempt to hide her irritation with the snobbishness she has endured. "It is tremendously annoying," she says. "To some people the phenomenal sales are simply proof that the books are trash – because popular books can't be any good and literary fiction is only for the cognoscenti, so sales of 500 are a mark of distinction.

"I have no objection to well-written romance, but I'd read enough of it to know that that's not what I had written. I also knew that if it was sold as romance I'd never be reviewed by the New York Times or any other literarily respectable newspaper – which is basically true, although the Washington Post did get round to me eventually. And that's only because I write book reviews for them." She laughs, then adds, "That's why I write book reviews for them."

Gabaldon is feisty, confident, openly irritated by the furore, or worse, the indifference with which her literary output is met. Partly that's an issue of genre, an entrenched disdain directed at all books that are popular – although it's hard not to notice that there seems to be an even greater opprobrium for Gabaldon since she is perceived to write for women, or perhaps because she is a woman.

It might also be that Gabaldon's own description of her transformation into a writer is practical rather than poetic. She applied herself to writing as an exercise, a problem to work through. It's prosaic, pragmatic, quite unromantic. "I don't plot the books out ahead of time, I don't plan them. I don't begin at the beginning and end at the end. I don't work with an outline and I don't work in a straight line. What I need to work at every given point and on any given day is what I call a kernel, an image, a line of dialogue, any little thing, just something that I can describe that is concrete.

"And so I describe it, as well as I can. I sit there and stare at that sentence or two. I take words out and I put words back. I juggle it, trying to make it euphonious and clear and elegant and all that, and at the same time at the back of my mind I'm kicking up questions."

Gabaldon talks quickly, but as she describes her creative process she breaks into a kind of rapid-fire monologue, talking herself through the process. "People begin to talk to me. Sometimes it's a line of dialogue, and I'll simply write that down. When it's that way, usually someone will reply to that and maybe that's just the first interchange, but then I can see the people and I can see where they are and what they're doing."

Confidence has evidently come with success because although Gabaldon knew as a child that she wanted to write, it was an ambition she never admitted. "No fringe benefits," she says with a smile. "My parents were both born in 1930. They grew up during the Depression. They wanted their children to have secure lives, to have a good salary and a pension plan. If I could've guaranteed that I'd be a best-selling writer, that would've been one thing, but nobody could say that. So I knew better than to say that was ambition.

"Also, for my father there was a social aspect. If you say, 'My daughter is a writer,' it can be a euphemism for 'She has no job.' Whereas it was important to him that my sister and I would do something socially respectable. For a while she got ahead of me in those stakes, when she went to Harvard and became a lawyer. But then I got a PhD, so I caught up."

Gabaldon's father was obviously a profoundly influential figure in her life. The 15th child of a New Mexican dirt farmer, he went on to first become a teacher and then a principal and part-time coach. After Gabaldon's mother, also a teacher, died, he fulfilled a long-held ambition and went into politics. "He got elected and worked in the state senate as a senator for 25 years," Gabaldon says.

Gabaldon's three children are grown up, and she and her husband, Doug Watkins, to whom she has been married for 32 years, spend their time between their homes in Scottsdale, Arizona and Santa Fe. I wonder what a typical day is like for Gabaldon, imagining a meticulously planned 24-hour period. "I work late at night. I'm awake and nobody bothers me. It's quiet and things come and talk to me in the silence. My husband gets up at around 5.30am, so I'll tuck him in around 9.30pm or 10pm and then I'll go and lie down on the couch with a book and my two dachshunds. If nobody needs me, and usually these days they don't, I'll fall asleep until around midnight. Then I go upstairs and work until 4am, and that's when I go back to bed for good. It suits me."

Fans of Gabaldon's books are ferociously loyal. They've created forums on the web where they discuss in minute detail the plots of the novels, the travails of the characters, perceived errors made by Gabaldon. They make pilgrimages to Scotland, and even have their own name – the Ladies of Lallybroch – based on the imagined place in Scotland from where Jamie originates. Early reactions to the new novel are decidedly mixed. I wonder if Gabaldon feels pressured by the weight of expectation? "No," she says. "There are always people screeching and upset that I did this or didn't do that. Basically they're upset that I didn't rewrite an earlier book they particularly liked.

"Every now and then, Janice (the woman who screens Gabaldon's e-mails] will forward me a particularly vituperative letter, reproaching me for what I did in this book. I've got form letter 13 for those people."

Good number, I say. "There actually is no 11, no 12," she says with another laugh. "It says, 'Not all books are intended for all people. Obviously this book is not for you but I hope that you enjoy whatever you read next whether it's by me or another…'"

What reaction does she receive? "About half the time I receive this apologetic letter saying, 'I'm so sorry. I didn't mean to go off like that, I was just so deeply emotionally involved in the book. I love your books.'"

She takes a sip of her Diet Coke and smiles.

An Echo in the Bone is out now (14.99, Orion)

• This article was first published in Scotland on Sunday, January 31, 2010