Literary mysteries: Who is writing the next book in 'The Girl with the Dragon Tattoo' series?

The question: Who is writing the next book in "The Girl with the Dragon Tattoo" series?

Lisbeth Salander will return to the page this September, but many fans are asking: How?

It's a long enough story it could probably use a series of its own.

First of all: Stieg Larsson, the Swedish author of the series, never saw his books in print. He died of a heart attack in 2004 at the age of 50.

At the time of his death, he had just sent the manuscript for the third book to his publisher, but the books had yet to be published.

"The Girl with the Dragon Tattoo," the first book in his series, was released in 2005 and went on to become an international bestseller. The publisher released the next two books, "The Girl Who Played with Fire" and "The Girl Who Kicked the Hornets' Nest" in quick succession.

To date, more than 75 million copies of Larsson's books have been sold in 50 countries.

Enter the controversy. Larsson and Eva Gabrielsson lived together in Sweden for 32 years, but never married. Gabrielsson was integral to Larsson's writing process — the two passed drafts back and forth for years. Under Swedish law, however, Gabrielsson was entitled to nothing after Larsson's death. Larsson did not leave a will, so the proceeds of the books, and the control of the series, went to his father and young brother.

Gabrielsson and the Larssons waged a very public war in the Swedish media for Stieg's estate. For a time it seemed like they might strike a deal, but ultimately they could not agree. Control of Lizbeth Salander, and the hefty checks from book sales and movie adaptations, remained with the Larssons.

So where will the fourth book come from? Before he died, Stieg hinted to friends and his publisher that he planned to write 10 installments of the Millennium series. In fact, he'd already completed a large portion of the fourth book.

Gabrielsson confirmed this in her own book, "There Are Things I Want You To Know," about her life with Stieg. She wrote that the fourth volume was to be called "The Vengeance of God" and that in it "Salander will free herself of her enemies and demons." Stieg had already written 200 pages.

But none of that will be in the fourth book.

It was suggested that Gabrielsson could finish Stieg's draft, but she has since changed her mind. "Stieg is dead," she told Spiegel Online. "There are three books. We should leave it at that."

The Larssons, however, are not leaving it at that. With his family's consent, Stieg's Swedish publisher Norstedts hired David Lagercrantz, a former crime journalist, to write the fourth book.

According to Norstedts, it will be an entirely original work, with nothing from the draft that Larsson left behind.

Lagercrantz is most well-known for co-writing the life story of a Swedish soccer star. His addition to the series will be released in September; it's called"The Girl in the Spider Web."

News about the new book, and the fact that it contains none of Stieg Larsson's original draft, has stirred up controversy in Sweden and beyond. The Millennium series has always been steeped in controversy, however, as some claim Stieg didn't write the first three books at all.

Although Stieg worked as a journalist for years, he was never known for his writing skills. He was even turned down for a promotion by an editor who told him that writing just wasn't his thing. After his death and the wild success of the series, several of his close acquaintances speculated publicly that he couldn't have written the books. Some suggested Gabrielsson was the true author.

Gabrielsson has denied the claim, saying only that the two worked closely on the project.

She has yet to comment on news of the forthcoming book.

This isn't the first time a series has continued on after the death of its creator. Eoin Colfer tried to recapture Douglas Adams' magic when he wrote a sixth book in "The Hitchhiker's Guide to the Galaxy" series, following Adams' death in 2001, though fans were left mostly disappointed.

When best-selling author Vince Flynn died in 2013, Simon & Schuster recruited a new author to keep Flynn's terrorist-fighting protagonist Mitch Rapp alive.

The Dune series went on without Frank Herbert and even Christopher Tolkien edited and unreleased some of his father's unpublished works.

What remains to be seen is if Lagercrantz can do Lisbeth Salander justice.

We'll see in September.