It has long been rumored that the late Swedish author Stieg Larsson, who penned the phenomenally popular Millennium Trilogy (The Girl with the Dragon Tattoo and its two best-selling follow-ups), had written a further sequel before his sudden death at age 50. (Watch a CBS report about the "Millennium" phenomenon.) Now, his family has confirmed the existence of an unpublished manuscript, raising the question: Will fans ever get to read it? Here, a brief guide to the tantalizing find:

So there is, in fact, another book?
Three-quarters of one, according to the author's brother, but it's not the book you'd expect. Joakin Larsson tells CBS News that Stieg sent him an email 10 days before he died (on Nov. 9, 2004, from a heart attack) announcing that another book was almost finished. The twist: Stieg Larrson had apparently decided to jump ahead in the series and write the fifth installment "because he thought that was more fun to write than book number four." The New York Times' Julie Bosman says: "The disclosure — should it be true — adds another turn to an already twisty personal story that is nearly as complicated as the plots of the Swedish crime mysteries that Mr. Larsson wrote."

How many Millennium books did Stieg intend to write?
It is widely reported that Stieg planned to publish 10 books in the series.

Will the new manuscript be published?
Not at this point, anyway, due to a "bitter dispute" between the Larsson family and the author's longtime partner, Eva Gabrielsson. Although Gabrielsson lived with Larsson for more than 30 years, the two never married, and so, under Swedish law, his estate and the rights to his books reverted to his family. Gabrielsson is now fighting in court for her share of the Millennium profits.

Who has the manuscript now?
Reportedly, it's in Gabrielsson's possession, but she has no right to publish it. Stieg's father, Erland, says he has "held it for a couple of seconds" but did not read it.

Do we know anything about its content?
Gabrielsson has refused to discuss the matter. Stieg's friend John-Henri Holmberg — the only other person known to have any insights — says he received an email from the author less than a month before his death discussing the book's setting, a remote island in the Canadian Arctic Archipelago. "The plot is set 120 kilometers north of Sachs Harbour, at Banks Island in the month of September," the email reportedly reads. "Did you know that 134 people live in Sachs Harbour, whose only contact with the world is a postal plane twice a week when the weather permits?... But there are 48,000 musk-ox and 80 different types of wild flowers that bloom during two weeks in early July, as well as an estimated 1,500 polar bears." According to the email, Stieg had written 320 pages of the projected 440-page book.

Sources: CBS News, The New York Times, Guardian, Associated Press, Encyclopedia Britannica