He has amazing deductive powers, an array of hidden weapons and the lethal reactions of a samurai. What's more Erast Fandorin - special agent, gentleman, polymath and all round lucky bloke - is capable of solving any mystery.

His cases involve murdered Russian generals, secret anarchist cells, and international lady criminals. Throw in a whiff of Great Power intrigue and a white-eyed assassin and you have a sure fire recipe for literary success.

In fact, the adventures of Erast Fandorin have made Boris Akunin - Fandorin's 51-year-old creator - wealthy and famous. He is the country's most successful contemporary author and in those terms the closest Russia has to JK Rowling. His novels have sold more than 20m copies, not just in Russia but also in the US, Britain and 30 other countries. In January the latest Fandorin mystery, The State Counsellor, appears in the UK.

A classical philologist, essayist, critic, editor and literary translator of Japanese, Akunin only started writing his Tsarist-era detective novels at the age of 40. Intriguingly, he doesn't consider himself a writer as such.

"I'm very un-Russian in this respect. I'm not actually a real writer. I do not have inspirations or things like that," he tells the Guardian in an interview in his Moscow flat. "I am more a sort of literary Frankenstein, creating formulas and growing my homunculi in a bell jar. I composed Fandorin of portions of literary characters which I found attractive, and then added a bit of my own recipe."

Fandorin, he explains, is a combination of three archetypes: British gentleman, Russian intellectual, and Japanese samurai. "He is very reserved, is always understating things. In this attitude he is very un-Russian and very, well, Anglo-Japanese."

Akunin began writing in the 1990s for Russia's new middle class. At the time, post-communist Russians had two choices of reading: classical masters such as Dostoyevsky or Tolstoy or pulp fiction.

Akunin spotted the gap. Realising, as he puts it, that every class needs a "literature it can read and enjoy", he invented a new kind of detective genre set in imperial Russia. Its young hero, Fandorin, is self-assured, handsome and foppish - but also emotionally insecure. (At the end of his first novel, The Winter Queen, his new bride gets blown up.)

"I was sort of tired of Russian literary tradition when you have to write in a very heavy style. Russian writers, Soviet writers, used to write in a very suffocating way even about things which are even not that serious. I prefer much more to write in easy style about serious things," he says.

Not everyone, though, is enamoured of Akunin's international success. Writing earlier this year in the London Review of Books, Perry Anderson dismissed Akunin as a "high-end intellectual" who had wasted his talents churning out "hugely successful pulp".

Russia, Anderson complained, is fixated on "pastiche versions of its dynastic past" and "retro-tsarist culture". Akunin is unperturbed by such criticism and is happy to admit that his novels are a clever "postmodern" game.

"If my readers want to take me seriously that's fine. But if not that's OK with me," he says. The Fandorin books are mainly set in the 1880s - an optimistic decade when both the west and Russia believed the problems of human existence could be solved with the help of technical progress and rationalism.

It was also an era of high tension between Britain, Russia and Germany - a bit like today. "Relations between Russia and Britain were even more awful in the 1880s. They were on the verge of war because of Afghanistan and all that. Britain was the enemy number one," Akunin notes.

In Akunin's fourth Fandorin mystery, The Death of Achilles, Fandorin's old friend General Sobolev is murdered with the juices of a rare Amazonian fern - a sort of 19th century version of the radioactive polonium used to kill the Russian dissident Alexander Litvinenko last year.

Akunin started writing undercover - the name is a pseudonym from a Japanese word that loosely translates as villain. His real identity - Grigory Chkhartishvili - was swiftly unmasked as the Fandorin series took off.

He was born in Tbilisi but grew up in Moscow. Last year when relations between Russia and Georgia dramatically worsened, the tax police took a sudden interest in Akunin's affairs. Although he is not an opposition figure as such, it is clear the Kremlin does not like him. He is not a fan of Vladimir Putin either, he admits. "I do not know personally anybody who likes what's happening in my country politically.

"I would like to live in a democratic society, which Russia isn't these days," he says.

Akunin refuses to appear on Russian TV, which is controlled and censored by the Kremlin. (His last TV appearance was on a show for children.)

A historian by training he is, however, generally upbeat about Russia's future. He says he is not dismayed by Russia's current authoritarian leadership or by the stunning political apathy of its middle class.

"My impression is that Russian society is still moving in the right direction. For the first time in Russian history tens of millions of people are learning to work, not to expect anything from the state, to be providers for their families. It's a revolutionary experience for many people," Akunin says.

Not every writer, though, shares Akunin's distaste for Russia's hawkish president. Over the summer Mr Putin had tea with Alexander Solzhenitsyn - Russia's most famous living writer. What did he make of this?

"Solzhenitsyn is so old and has so many things to his credit that I don't want to criticise him for anything. But I think that in Russia a writer and an artist generally should always keep a distance from the power and the state," he says. "It's the only healthy way to live and survive in this country." He adds: "Speaking of serious literature I do not think anything of the scale of Tolstoy or Doystoyevsky has been here recently."

Akunin's literary success, meanwhile, means he is free to live wherever he wants. He divides his time between Moscow and Saint-Malo in Brittany - "a quiet provincial town" where he is free to write undisturbed. He spends the morning writing but devotes the afternoon to sport and playing historical strategy games on his computer.

Akunin has written full-time since October 2000, when he gave up his job on the prestigious magazine Foreign Literature. He is married but has no children. "Now I'm free I work non-stop, no weekends, no holidays, nothing," he says. "Nobody can exploit you as harshly as you can exploit yourself."

Two Fandorin novels, Turkish Gambit and The State Counsellor, were made into big-budget movies, which broke Russian box office records in 2005. A play based on Erast Fandorin is showing next to Red Square.

Akunin is working on a new project - Cinema Novel - a cycle of 10 short novels combining words and pictures. A TV series will follow. The characters are new; one senses that he's had enough for the moment of Erast Fandorin.

What's the novel about? "It's a spy story about world war one set in Russia and abroad. It has two protagonists. One of them is Russian and the other is German," he explains. The result of their battle is that both countries lose their empires, he says.

What Russia reads

Russia produces fewer books than it did in the Soviet Union - with around 100,000 titles published in the past year. Under Communism there was a centralised book and periodical distribution system. Its collapse has made life difficult for independent publishers and has led to a fragmented cultural scene. None the less, sales of science fiction novels surged 30% in 2005 in Russia. Science fiction accounted for 8.7% of Russian book sales last year - behind children's books, mysteries, philosophy and text books. Maxim Kantor was heralded as the new Tolstoy after his debut novel sold out within four weeks. The New York Review of Books says the most significant literary enterprise is Novoe Literaturnoe Obozrenie, started in 1992. It is Russia's leading literary journal.

· The article above was amended on Saturday September 29 2007. This article about the Russian author Boris Akunin said that Perry Anderson had written about him in the New York Review of Books. In fact Perry Anderson's article appeared in the London Review of Books. This has been changed.