David Mitchell is weaving his way around a circuit of yurts erected for the Edinburgh Book Festival, to get to his seat for an afternoon event, but his journey is a puttering one, punctuated by a convivial form of crowd-mobbing.
A ticket attendant stops him excitably to discuss a scene from Star Trek 7 which he mentioned in his talk earlier that day (and mistakenly credited to Star Trek 6, he is told); a middle-aged woman quizzes him about the childbirth scene in his latest, historical novel, The Thousand Autumns of Jacob De Zoet (Sceptre) that left her book-club so discombobulated; a man interjects with a story of how his wife reads Cloud Atlas (2004) every year and "she finds something new each time"; a fellow-author wants his book signed; another wants to shake his hand.
Mitchell's fans are evidently not a shy, retiring bunch and he receives them variously with an earnest summary of 18th-century obstetrics, an admission of defeat on the intricacies of Kling-on culture and more generally, a mild air of surprise.
This level of attention is not what he's used to, he confesses, after finding retreat behind the back of the writers yurt. In the eight years he lived in Hiroshima, where he wrote his first, instantly successful novel, Ghostwritten (1999), he wasn't stopped on the street once. Japan does not have a huge fiction market, he explains.
Neither is he bothered in the rural stretch of West Cork, near the town of Clonakilty, which has been his adoptive home since 2002, with his Japanese wife and two children. "People know who I am but no-one draws attention to it. There's a very true Irish epigram that says: 'In Ireland, being famous is nothing special'."
A rangy figure who wears a bulging rucksack dangling with Velcro pouches and hill-walking boots, Mitchell looks more like a geography teacher on a field trip than a literary enfant terrible, despite having the classic CV for one: he published the acclaimed Ghostwritten when he was barely 30 and was duly placed on Granta's list of Best of Young British Novelists in 2003. He even has the natural good looks that could pass for rakish, were they not modulated by modesty.
From his oeuvre of five novels, not one has gone unacknowledged by book prize selectors; a two-times Booker shortlistee, he has a third nomination on this year's longlist. What must be doubly enviable for "literary fiction" writers of his ilk is that the critical adulation has been accompanied by mass market success - he has sold over a million books. The Booker nominated Cloud Atlas became a book-club sensation after Richard and Judy hailed it the best read of 2004. First edition copies are now said to sell on eBay for £500.
Yet he appears at odds with his fame ("I'm not yet willing to agree that my face might be recognisable", he says, incredibly, given the hero worship half an hour earlier) and emanates a humility that does not appear to be a sly contrivance, with one eye to the mirror. When someone asks him for a signature, it turns out not to be a hurried spider's scrawl but an elaborate confection that verges on a sketch, ranging across the page in swirls of blue felt-tip. "Well, if they've waited for an hour in a queue to have their book signed....", he says, providing them with just reward for their patience.
As a British writer raised in Malvern, a move to London might have been the most predictable step for him at the outset of his career, but neither Mitchell nor his fictional worlds have been rooted in the capital, or any one metropolis. Nor has he attempted to write the kind of state of the nation novel that, he wryly suggests, barely conceals the narrow preoccupations of the urban middle-classes.
His distance to it, in part, appears to be a career management strategy, not just as a way of circumventing parochialism in his writing but as a way to avoid the heady distractions of his own success. "I couldn't see how I would ever get any work done if I lived there. The paradox in all careers is that without success, you couldn't do it, but success itself is not very good for creativity," he says.
His fictional universes traverse a range of geographies and genre-hop not only from book to book, but also within it; Cloud Atlas's criss-crossing narrative voices combine historical journal with nourish thriller and science fiction, while Ghostwritten encompasses nine lives across Okinawa, London, New York, Tokyo, Mongolia and St Petersburg, and the latest book traces the decline of Dutch rule in the Japanese outpost, Dejima.
It is all contrived to be genre-defying writing. The novel on which he is currently working is a case in point. This, and the one after it, will feature the erudite Dr Marinus – who teaches medicine to Japanese locals in The Thousand Autumns – as a linking motif, although his presence should not lead us to presume that the three works will comprise a historical trilogy. "The nature of the (current) book makes it difficult to generically pinpoint. How would you locate the genre of a book which contains both a woman with post-natal depression, in the upstairs of a pokey house with her neighbours downstairs watching the Apollo moon landings? Part two of the question, and the novel, is a place where oil costs $1800 a barrel and where gangs of men with guns are draining the oil tanks."
Recurring themes that unify the widely ranging subject matter in his books include non-communication, and the idea of characters preying on others, he reflects. What also persists and re-emerges is the idea of voyage and a pursuit of alternative worlds, repeating tropes in his fiction and also his life. As a 24-year-old English literature graduate, he found himself "rootless and jobless", and struck by enough wanderlust to take a job abroad. "I had been in Japan a year or two and I thought 'what next?' Then, a great stroke of luck: I got a job at Hiroshima University, teaching eight hours a week. It gave me the time and space to write, and that's where I wrote most of Ghostwritten."
He stayed to write his second, number9dream (2001), before settling in Ireland, except for a six month stint near Leiden in the Netherlands to research The Thousand Autumns.
Ireland was chosen for its cultural neutrality which he could never have been achieved had he stayed in Japan, and which his wife could not have felt had they re-located to the Worcestershire of his youth.
"We needed somewhere to live and cities are great but they were taking more out of me than I was taking out of them. And it's a third country. We can't blame each other for the host country's shortcomings. It's no-one's fault when things don't go as you wish."
An inter-racial marriage in Japan did make him feel conspicuous, he adds, in a way that his family does not feel now. "In Japan, especially small-town Japan, you feel self-conscious just being a tall, white dude, so walking along with my wife was just a twist to the usual gaijin self-consciousness. In West Cork, not at all. It's a slightly different planet."
Still, Japan continues to maintain a hold on his imagination, and its politics and history have been corralled for all but one of his books. It won't be in his next novel, but it will reappear to form a quarter of the book after that.
"Wherever you are in your 20s, you collect a lot of loot there that you will later utilise. It's a barefaced Orientalist statement [but] if you spend a good part of your youth in Asia, it gets under your skin in a particular way. The place, Asia, and your youth, get tied up."
His original urge to write was a calling as strong and certain as genetic hardwiring. He wrote a novel prior to Ghostwritten that never managed to find a publisher ("Thank heavens. Watch out for getting published too early"), and he expects, rather than hopes, for an upward trajectory in his literary skilfulness with every book. "I would be very depressed if I didn't think I was becoming a better writer with each book. How disappointing it would be if your first book was the best. You should be getting better each time."
One senses a very exacting inner judge in Mitchell; he tends to answer questions after a moment of quiet deliberation, working his lips silently in an effort to speak, one imagines, in the sparkling sentences he is known to write. His research process is meticulous and multi-layered: "First I do the research for world building, then the research for scene making. The third category of research is to help me finish my sentences, so I need to find out how a man shaves in the 18th century so that I know whether a middling clerk (such as Jacob De Zoet) can afford it."
The book he would most like to re-write, he adds, is his "difficult second album", number9dream. While we are on the subject of past imperfections, his books' shortcomings are all too clear, and grating: "I think to myself 'look at that metaphor, it's so pleased with itself' or 'look at that ten-page drivel'."
His latest novel could be seen as his most conventional historical fiction. While commended for imaginative and verbal pyrotechnics, it has faced some charges of disengagement from the politics of the present and that, according to a New Yorker review, "there is something a bit mystifying about its distance from contemporary life".
Mitchell appears visibly agitated by this view. "If you write truthfully about human life, by which I mean the human heart and how it interacts with the world, you don't have to strive for contemporary relevance. If a book like Wolf Hall meant nothing today, we would not have got past page two.
"The essence of 'we' is universal and no different to two hundred years from now, if it's truthful to the human experience. How that 'we' is pummelled and moulded is locally determined. The corruption of the Dutch East India Company is the same as the corruption at Enron."
Yet the defence of historical fiction is accompanied by the admission that he is leaving it behind, to some degree. Changing the terms of storytelling with each book is deliberate because it allows for infinite possibilities: "The ideas I will tend to choose for novels are ones that least resemble books I have already written. My curiosity leads me to choose different types of books to write. I rather encourage this trait because it's the best way I can see of avoiding the condition of writing endless versions of the same novel, which can lead to premature artistic death."
So far, it seems to have worked. Each of his novels have brought greater acclaim, although it surely must be hard to fend off performance anxiety each time he tries to follow up the last 'great' work of fiction? Apparently not. He has "worked out how to feel immune to it by agreeing with myself that the biggest question to answer is 'how do I make 'this' book work?'
What of the Man Booker nomination, third-time around? "What? Do I want to w-i-n?" he pauses, and works his lips. "I felt honoured and pleased (by the nomination), but it's the guy who approached me to tell me his wife reads Cloud Atlas once a year that I think is just so great. If I had to choose one out of the two, I'd choose the man. I want to do this until I die. He enables me to continue to do what I love. Prizes won't do that for you."
I travelled from London to Edinburgh by rail with East Coast Trains: advance return fares, booked online, start from £26 Standard Class or £92 First Class: book via www.eastcoast.co.uk, call 08457 225225 or visit any staffed station.