I just watched the movie and although I think that the movie stays pretty on course with the book, I was wondering why they didn't add the last chapter where it looks like Alex is cured. It makes me think if I was directing would I want to put in that last chapter or leave it out. I think it makes a huge difference in the entire message of the book. Without the chapter I would assume that Alex would go back to being his old self, which would mean all the therapy and treatment was for nothing. But with the last chapter it shows that the treatment was successful and leaves the book with kind of an odd positive ending.