Is the third and final novel in the million-selling Millennium Trilogy by Swedish writer Stieg Larsson. It was published posthumously in Swedish in 2007 and will be published in English in October 2009. The Swedish title literally means "The Air Castle that was blown up". Luftslott ("Air castle") is used in Swedish to designate a pipe dream.

The novel is a direct sequel to The Girl Who Played with Fire, and is part of the award-winning Millennium Series by the late Swedish columnist Stieg Larsson, and will feature most of the same characters from the first two novels.