Stieg Larsson's fourth Dragon Tattoo novel set in Ireland
The fourth book in Stieg Larsson's hugely popular "Dragon Tattoo" series features the twin sister of the series' protagonist Lisbeth and is partly set in Ireland.
The bestselling Swedish author’s fourth manuscript in the cult series, was almost three quarters of the way to being completed, which was more than previously first thought, said Kurdo Baksi.
Speaking at the Edinburgh international books festival, Mr Baksi said one of the new novel’s main characters was Camilla Salander, whose twin sister is the series' heroine, and is set "between Ireland, Sweden and the US".
He added there were 10 novels planned by Larsson, and the long-rumoured "fourth" novel was in fact the fifth in the series.
The disclosures will delight fans of the Millennium trilogy, which has sold more than 32 million copies worldwide.
The books were published after his death in 2004 and have become a phenomenon, making £20m for his estate. A Hollywood film is in the works.
Discussing his memoir, “Steig Larsson My Friend”, he claimed he was shown a draft manuscript by Eva Gabrielsson, Larsson's partner of 32 years, shortly after the author’s sudden death from a heart attack at 50.
The Kurdish-born journalist colleague said that the manuscript as it stood would "make the perfect Hollywood film", The Guardian reported.
"It is at 260 pages at the moment – about 70pc complete,” he told the festival on Monday.
“Eva has said the book is not so complete. She took the book after Stieg died and showed it to me and his father."
But he argued that an attempt to complete it posthumously would be inadvisable because ghost writers "would not respect Stieg Larsson's style".
But his comments were disputed by Miss Gabrielsson, who said the book, which was in draft form on Larsson's computer, was less than a third completed and "does not hang together”.
The architectural historian, who has also written her own memoir, has attacked Mr Baksi's representation of Larsson as a sloppy journalist, in which she described as "pure slander" and called for its withdrawal.
Speaking about his relationship with Miss Gabrielsson, Mr Baksi told the festival: "She asked me, 'are you with me or with the family?' And I said I am not with you, and not with the family.
“I have known his brother for a long time, I feel part of the family. I want to be a friend to both you and them.
“The first two years I was with her, I did everything for her, speaking with the lawyers, talking to her every night. But I can't not say hello to the family."
He added: "Eva was not the only woman in his life. He had some moments here and there – I know of four of them.
“You don't need to worry about Stieg Larsson. He had a good time in his life."
After his death, Larsson left behind three manuscripts about crime-solving computer hacker Lisbeth Salander.
Published posthumously as the Millennium trilogy, they became one of the literary sensations of the decade.
But the fourth book has been the centre of an extraordinary legal battle.
Because Larsson and Miss Gabrielsson never married, his estate defaulted to his estranged father and brother under Swedish inheritance laws, and with it the multi-million pound fortune.
The Larsson family therefore own the rights to the fourth book – said to number 320 pages – but Miss Gabrielsson will not hand it over to them.
She has refused to publish the script – or disclose any plot details – unless she is given full rights to the Millennium series, and fans have stepped in to help with her fight