So Stephen King swears in his introduction about as much as one of the characters do. But he also gives a lot away, about how people approach an author to adapt a work. And Darabount has an interesting philosophy to explain his success and why he's not working at a McDonalds.
Scenes aren't just deleted with the usual irritating "omitted" sign, but we actually get to see the screenplay here. And we are told why some scenes weren't used.
After the script, we have the storyboard (or at least a part of it). Apparently, not every scene was storyboarded, just the ones that weren't straight forward to shoot.
No, it's not a complete making of, but this is definitely one of the better screenplay books I've seen.
If you just want to see the original story, get "Different Seasons" by Stephen King. If you want more insight into the making of from everyone's point of view, there's a great documentary with the DVD. But if you're interested in the process from a writer's (and director's) point of view, this is the book to get.