Latest Stieg Larsson novel isn't by Larsson – and some readers are not happy

'The Girl in the Spider's Web' brings back characters Lisbeth Salander and journalist Mikael Blomkvist as they join forces to hack into the US National Security Agency in a plotline that includes stories about hacking, corruption, and national security.

Before it has even hit shelves, the latest Stieg Larsson novel is already generating controversy – largely because it's not actually by the late Mr. Larsson.

"The Girl in the Spider's Web," by Swedish author David Lagercrantz, will be published August 27 worldwide and Sept. 1 in the US.

It is the first novel in the popular "Milennium" trilogy not to be written by Larsson. The third book, "The Girl Who Kicked the Hornets’ Nest," was written by Larsson but published posthumously.

"The Girl in the Spider's Web" brings back characters Lisbeth Salander and journalist Mikael Blomkvist as they join forces to hack into the US National Security Agency in a plotline that includes stories about hacking, corruption, and national security.

"The secret they are both chasing is at the center of a tangled web of spies, cybercriminals, and governments around the world, and someone is prepared to kill to protect it," reads the book's synopsis.

"[T]here are some surprises in store for readers as well, including the introduction of Silicon Valley as a locale and a character from the National Security Agency in a central role," author Lagercrantz told USA Today earlier this year.

Of course, the book's highly-anticipated release isn't without controversy.

The idea of Larsson's original three-book trilogy continuing with a fourth book not authored by Larsson has upset some readers. And while Larsson's father and brother authorized the new book, the late author's former partner said in March that Larsson did not have a long-term plan for the series and has publicly opposed "The Girl in the Spider's Web."

“Everyone thinks there was some grand scheme,” Eva Gabrielsson said earlier this year, “but no, he had no plan for the first three books and when he started writing the fourth one, it was spontaneous. He still didn’t have a plan.”

In a statement, Lagercrantz said, "Stieg Larsson was a master at creating complex narratives, narratives made all the more forceful because of the journalistic authority with which they were originally written. That was something that informed my approach to book four, and I'm confident Millennium readers will identify with the storylines in 'Spider's Web.'"

Readers hungry for a taste of the book before its Sept. 1 release can read an excerpt here.