I heard King wants a series, like on HBO to cover the books and do them justice. Then again, he did rush the final three volumes because of a fear dying before finishing them, in lieu of his accident where he got run over. If I remember correctly, he even admitted that the ending was going to piss people off. I wonder how Abrams would end the series.
As best as I can describe it. The Dark Tower Series is a story that spans 7 books (and one short story and an ongoing comic books series). Its was first published in book form in 1982 (I think there was a few chapters King previewed in a Sci Fi magazine a few years before that) and was title "The Gunslinger". In this story the reader follows a character named Roland (who is a character made in the image of Clint Eastwood from the Spaghetti Westerns) who is on a chasing a "Man in Black".
What is wonderful about the series is that it turns into an Epic Story with interesting characters, Fantasy and Sci Fi elements, and alot of cultural references(Spaghetti Westerns, Comics, Movies, songs, etc..). Not to mention, King manages to tie his previous stories to these novels in some form (Salems lot, The Stand, etc...) and he has even written books as a companion to this series (The Talisman, Hearts in Atlantis, etc..)
The beauty of this series was he spent time writing it. Every 7 years or so another novel would come out (Imagine having to wait seven years for each book Potter fans). The first four novels are amazing, I even remember tearing up in the fourth one.
Sadly though, he was involved in a hit and run and was seriously worried of finishing the series before he died. Hence, there was no longer the seven year wait. Between 2003 to 2004 his churned out the final three volumes and rewrote the first novel to adjust the storyline. I am probably being a bit harsh on the last novels, since they are not that bad, but could have been better had he spent some more time on them. In his epilogue for the final volume, he even admits the ending was not going to make people happy. I still recommend the series to anyone, I do not regret reading it and who knows, he may rewrite the final novels.