The final book in the Millennium series completes the major story started in the second book. In some ways I thought this was the best of the three, even though it is not a mystery but more of a judicial and political thriller. Like the first two books, this one occasionally suffers from an over-abundance of exposition (rather than letting the details develop naturally), but overcomes it all with a solid story which keeps one engaged throughout. Well, at least engroused through most of it. Like the first book, there is a surprising amount of post-peak wrap-up that one wouldn't normally expect in a thriller and it drags a little after all of the earlier build-up.
Larsson died before any of these books were published, which in-and-of-itself is a remarkable achievement, and its a shame we won't have more stories of this group of characters. Thankfully, this book wraps up everything quite neatly. Off the top of my head I can't think of any outstanding or unresolved plot elements. There are certainly minor things which could have been explored in future books, but nothing which leaves you wondering what the author had eventually intended.