In Hollywood's Stephen King, Magistrale is best when talking about how the movies based on King's works differ from the works themselves. When he evaluates movies that are very close to the stories as written, he tends to get bogged down in literary criticism, which is not what this book is supposed to be about.
The interview with King at the beginning of Hollywood's Stephen King is one of the best parts of this book. In it, you get the impression that King writes his stories on an emotional level, aiming to grab the reader and shake him silly. As a college graduate and former English teacher, he can probably sling the lit crit with the best of them, but he seems to be aiming primarily for entertainment rather than edification.
To analyze King's stories may be to find things in them that aren't really there. In fact, Magistrale delves into psychoanalysis of King from time to time, talking about what makes him tick. This type of speculation leads nowhere.
On the other hand, Magistrale's discussions of the films and how different directors and screenwriters have adapted them is quite interesting. He even takes on Carol Clover and her book, Men, Women, and Chainsaws. Although I agree with Clover in this case, Magistrale makes a good case for his argument.
In this book, Magistrale wisely limits himself to examining about twenty films and series based on King's novels, novellas, and short stories. He notes that the best adaptations have been on his shorter works, which allow a director to add to the story rather than be forced to subtract. Carrie, Misery, The Shawshank Redemption were all short stories or novellas rather than full-length novels.
It isn't necessary to have seen many of these movies or to have read much King at all to enjoy the commentary in this book. In fact, I didn't even realize that The Shawshank Redemption was based on a King story until I read this book. For a book based on a college course, this short volume is surprisingly readable and entertaining.