The New Yorker on Stieg Larsson:
"Another question that has been raised about the trilogy is: Who wrote it? A co-worker of Larsson’s at Expo, Kurdo Baksi, suggested in a recent memoir, 'Stieg Larsson: Our Days in Stockholm,' that Larsson did not have a talent for writing."
I've read only the first book of the trilogy but it certainly reads like the work of a man with no talent for writing. I say he's the author.