If you are talking about Elemental: Destiny Embers: There will be a campaign exclusively for the owner of the book which will be splitted in four parts. I don't have my book yet, but I think the additional campaign will either attend the book's story or will continue it.

I ordered it two days ago on amazon.de and today I hold it in my hands.

I agree with J913B

The downloadable content seems to be named after the "books" in destiny ember, so It doesn't seem like it will continue the story

I also don't think that the sequel would be as good as a campaign then a book, it would be nice to have to complement or reenact the story, but I think i'd prefer a book to really continue the story

I'm wondering if the book forshadows goodies coming up in the game.  A large part of the book takes place in a huge undergound country/city.  Does this mean that future expansions of EWoM will allow undergound exploration?  (rubs hands with glee)  Cuz I love the idea of establishing cities undergound, with tunnels leading to the pathetic world of the surface dwellers.... 

Frogboy, please tell me this ability is coming!