From amazon.com:

Continuing Stieg Larsson's Millennium Series.

In this adrenaline-charged, up-to-the-moment political thriller, Stieg Larsson's Lisbeth Salander and Mikael Blomkvist are back. The troubled genius hacker and crusading journalist thrilled the world in The Girl with the Dragon Tattoo, The Girl Who Played with Fire, and The Girl Who Kicked the Hornet's Nest, which have sold more than 80 million copies worldwide.

David Lagercrantz is a Swedish journalist and best-selling author of fiction and nonfiction. He was hand selected by the Larsson estate to write this standalone sequel based on Stieg Larsson's characters.

From amazon.com:

The sixth Lisbeth Salander story in the Millennium Series - the crime-fiction phenomenon that has sold more than 90 million copies worldwide.

Mikael Blomkvist is trying to reach Lisbeth Salander - the fierce, unstoppable girl with the dragon tattoo. He needs her help unraveling the identity of a man who died with Blomkvist's phone number in his pocket - a man who does not exist in any official records and whose garbled last words hinted at knowledge that would be dangerous to important people. But Lisbeth has disappeared.

She's sold her apartment in Stockholm. She's gone dark. She's told no one where she is. And no one is aware that at long last she's got her primal enemy, her twin sister, Camilla, squarely in her sights.

In the end, it will be Blomkvist - in a moment of unimaginable self-sacrifice - who will make it possible for Lisbeth to face the most important battle of her life, and, finally, to put her past to rest.

From amazon.com:

From the author of the number one international best seller The Girl in the Spider's Web, the new book in the Millennium series, which began with Stieg Larsson's The Girl with the Dragon Tattoo.

Lisbeth Salander, the girl with the dragon tattoo, the brilliant hacker, the obstinate outsider, the volatile seeker of justice for herself and others - even she has never been able to uncover the most telling facts of her traumatic childhood, the secrets that might finally fully explain her to herself. Now, when she sees a chance to uncover them once and for all, she enlists the help of Mikael Blomkvist, the editor of the muckraking investigative journal Millennium. And she will let nothing stop her - not the Islamists she enrages by rescuing a young woman from their brutality; not the prison gang leader who passes a death sentence on her; not the deadly reach of her long-lost twin sister, Camilla; and not the people who will do anything to keep buried knowledge of a sinister pseudoscientific experiment known only as The Registry. Once again, Lisbeth Salander and Mikael Blomkvist, together, are the fierce heart of a thrilling full-tilt novel that takes on some of the most insidious problems facing the world at this very moment.