The worldwide sensation sparked by the Millennium crime trilogy put Swedish crime fiction very much on the map and turned its author, Stieg Larsson, into a name as synonymous with Sweden as Abba or Björn Borg.

Despite the enormous success of the books, a definitive posthumous biography of Larsson by Swedish author and journalist Jan-Erik Pettersson has only recently been published in English.

“I spoke with the publisher and we agreed it was strange that despite the gigantic success, even in 2009, nobody had done a book about Stieg Larsson himself,” says Pettersson.

“Even though we had worked together and shared similar political ideals, I didn’t know him personally, which helped because we didn’t want to produce a tribute kind of book and I wasn’t so keen on lingering on the aspects of the family conflict for example.”

Entitled, “Stieg: From Activist to Author”, the book was originally published in Swedish in 2010 and portrays Larsson as a deeply politically motivated personality with an incredibly prolific creative drive, always on the lookout to try out new things.

The irony, bearing in mind his success, is that writing books was apparently merely a fun hobby for Larsson.

“He certainly wasn’t someone who dreamed of becoming a best-selling author. It is strange in these times that in this media age we see so many people desperate almost to be famous, regardless sometimes of what for,” says Pettersson.

“Stieg wasn’t like that. Like some other really well-known Swedes, his popularity was almost by accident, someone who quietly ‘gets on with things’ but still gains recognition. It is similar if you like in the case of Astrid Lindgren, or Ingmar Stenmark,” he adds, referencing the famous children’s author and Olympic gold medal alpine skier.

Larsson was also fortunate to be riding a wave of interest in Nordic thriller writing, headed by the likes of Henning Mankell and perhaps to a lesser extent Jan Guillou.

Starting in the late 1990s, they had both laid the groundwork not just in Scandinavia but also in Germany, which also proved to be helpful in bringing attention to Larsson’s books.

In the biography, it is revealed that Larsson preferred American and British thrillers to their Swedish counterparts.

His special talent, according to Pettersson, was in identifying a common desire for something that combined the Anglo-Saxon style with the more earthy, socially engaged values of Scandinavians.

“He knew people liked the realism of the Swedish authors, but Larsson added touches, played with the characters more,” he explains.

“Salander, for example, is almost a cartoon-like figure, far removed from your ‘average Swede’. At the same time other, types in the books are completely believable.”

Those reading the biography hoping to find out how much of the Millennium books were autobiographical, and perhaps who the role models were behind the main protagonists, are in for a disappointment, however.

“I think all authors base characters on certain real people or events, and Stieg was no exception, but there are no obvious direct influences,” says Pettersson.

“Those who work at Expo, for example, would recognise some of the characteristics in certain people, the motorcycle gangs for example, in the books without necessarily being able to put a name to them. The same could be said for the Vangers as well, with their disturbing extremist background, which was typical of many such families at the time.”

Similarly it is natural to see parallels between the Millennium magazine of the books and Expo, which was such a huge part of Larsson’s life.

“I think he saw Millennium as the dream scenario for Expo. The former had the kind of resources and readership that Stieg would have loved to have in real life,” says Pettersson.

He adds that, the more he researched the book, the more he was almost in awe of how much work Larsson was able to produce given the immense pressure he was under and which probably led indirectly to his early death.

Another revelation, which becomes clear throughout the book, is how Larsson was aware at such an early stage of the danger posed by far-right groups and how their growing influence around Europe would inevitably lead to the formation of organised less overtly racist, but equally dangerous political parties in Sweden.

Larsson realised there would be a direct link from the National Front in Britain and Le Pen in France, for example, to the Sweden Democrats today.

The question remains, though, how circumstances played their part in the success of the books – As the old saying goes “No-one sells like a dead pop star”.

While it will never be known whether Larsson’s untimely death helped the books become more popular, Pettersson agrees that it’s almost impossible not to speculate on what may have happened had he lived.

“The fact that he died helps feed the myth of course,” he says.

“We do know he was a prolific writer and had plans to write many books, but what it clear is that he would have used the attention and influence to push his political agenda and promote other projects. He said he would never be comfortable with the whole idea of ‘sitting on TV sofa doing the rounds of chat shows’, although whenever he was interviewed he was clever enough to get his points and motivations across.”

There is no doubt that “Stieg” won’t be the last book written about the late Swedish author, but it is an excellent in-depth look at the man behind the book and the phenomenon, not just of the trilogy itself but also the popularity of Nordic thriller writing.

Published in the UK in March by Quercus Publishing, the book will be available in North America in the autumn through Sterling Publishing.