Uncovering the truth behind Stieg Larsson ahead of the UK cinema release of The Girl Who Played With Fire

But with as much mystery surrounding the late Swedish author's life as his books' controversial characters, is the truth about Larsson stranger than fiction?

WHEN The Girl Who Played with Fire opens in British cinemas next week, it will mark another yet astonishing chapter in the extraordinary story of the Swedish novelist Stieg Larsson, who in the past few years has sold more books worldwide than anyone except J K Rowling.

Larsson created three blockbusters in what he called his Millennium series - The Girl with the Dragon Tattoo, The Girl Who Played with Fire and The Girl Who Kicked the Hornets’ Nest.

Having racked up a staggering 27 million sales in 41 countries, all three books have been turned into films, the first of which has grossed more than £2m in box office sales in the UK alone and more than $100m worldwide.

The DVD release of the film in the UK has also been phenomenally successful, making The Girl With the Dragon Tattoo the biggest selling foreign language DVD of the year so far.

Yet Larsson did not live to enjoy his success. He died of a heart attack at the age of 50 in 2004, only a few months before the first book in the trilogy was published, became a best-seller and turned him into a literary sensation.

Why? Mainly because Larsson is such a compelling story-teller and because the two main characters in all three books - Lisbeth Salander, a rail-thin, bisexual, tattooed computer hacker who is the ‘Girl’ in the titles and her unlikely colleague, middle-aged investigative reporter Mikael Blomqvist – are such memorable characters.

In the first book and film, Mikael and Lisbeth join forces to unearth the mystery of a young woman from a prominent Swedish industrial family dynasty, long missing and suspected dead.

They discover unpleasant truths about the treatment of women in Sweden and the elements in Swedish society historically attracted to Nazism.

The Girl Who Played with Fire takes a different tack - Lisbeth becomes the prime suspect in three murders and is the subject of a nationwide search. But Blomqvist believes she is innocent and moves into action to clear her name.

Larsson’s posthumous success has made him a household name in Sweden, and ever since his untimely death, the nation’s press has regularly unearthed new controversies about him.

There have been rumblings (some promoted by friends) about whether he really had the talent to write these books himself.

Several biographies of Larsson have either been completed or are in the works and 10,000 tourists a year take the Millennium Walking Tour, organised by Stockholm’s City Museum, which includes city locations described in the three novels.

Then there’s the feud between members of his family and Eva Gabrielsson, his partner for more than 30 years.

They never married and a will he made as a young man was declared invalid. At stake are the proceeds of his estate, last valued at £20m, but increasing daily with every book sold. Gabrielsson also possesses the draft of Larsson’s fourth novel, but is refusing to hand it over to his family.

Even the circumstances of Larsson’s death have come into question. Coronary thrombosis was the official verdict, but outlandish theories continue to be aired.

Larsson, a committed left-wing activist, had enemies among Sweden’s far-right and there is wide speculation that he may have been murdered.

Top British crime fiction reviewer Barry Forshaw, who has written a Larsson biography, The Man Who Left Too Soon, has his own convictions about such theories.

First, he is convinced that Larsson and no-one else wrote the three novels.

He said: “The evidence is that here was a man who may not actually have been obsessive-compulsive, but was certainly a workaholic and was capable of writing such massive books.”

Yet while Forshaw admits Larsson had the ability to write gripping page-turners, he has reservations about his writing style.

“When my book was published, I did a lot of interviews with the Swedish press,” he recalls.

“It was tricky territory, in a way, because he’s like a national treasure to most Swedes.

“I said I thought he was a 'good-bad’ writer. He’s a popular novelist, an heir apparent to people like Thomas Harris (Hannibal Lecter’s creator).

"But his books are full of implausibilities. Lisbeth is more of a super-heroine than a real person. And Larsson’s prose style is inelegant. Luckily, a lot of the Swedes I talked to agreed with me.”

Intriguingly, Forshaw thinks the films improve on Larsson’s books.

He said: “There’s less extraneous material in them. They’ve been through an editing process.

In the film of The Girl with the Dragon Tattoo, for instance, there are fewer sexual conquests for Blomqvist. And it works better. It’s more believable.

“There’s little evidence Blomqvist is handsome or charming, but in the books every woman finds him irresistible.

I think Larsson regarded Blomqvist as a version of himself, so he made him a ladies’ man - as Ian Fleming did with James Bond.”

Certainly the three films have been amazingly successful. Between them they accounted for half of all box office takings in Swedish cinemas last year.

Before she took the role of Lisbeth, Swedish actress Noomi Rapace, 31, was moderately well-known for her work on stage and in art-house films. Now her countrymen regard her as a superstar.

But she gives full credit to Larsson for the success of his books and the films that followed.

"I think Stieg was pretty brave,” she said.

“He wanted to bring up things we don’t like to talk about, or like to ignore. In Sweden everybody has this perfect surface. Everyone’s very polite and controls their feelings.

“For instance, there’s certainly violence against women here, but it gets swept under the carpet. We have immigrants, but you don’t see them in the centre of Stockholm - a lot of people here don’t feel part of this society.

"And we still have old Nazis, Swedes who agreed with Hitler. We’ve never addressed this."

“Stieg was working against all those things and he wanted to force people to see those problems. The most depressing thing is, we’re afraid of talking about them.”

The Girl Who Played With Fire is released in cinemas on August 27.