I read Story by Robert McKee after I read The Story Grid and I found Shawn's explanations and descriptions more precise and to the point than Robert's. I also really like how Shawn, for the most part, uses a single story (The Silence of the Lambs) in his examples and how he keeps going back to it. Using a single story, I felt, helped me better grasp the context of each example and allowed me to 'grow' with the dissection of the entire story. The grid itself was also extremely useful as it provided me with a framework, a cheat sheet that I could reference at any time to understand where I was in his overall analysis of the story.
