This book started off promising, explicitly describing the "secret" language (such as the Hermann Chord, nonfunctional harmony, and Avro Part's compositional techniques), but then in the middle, the author started analyzing the scores without mentioning any major breakthroughs.
I'm not a movie person, so a good deal of the movies mentioned were lost on me, and for most of the rest, I will need to do another listen-through. That's not a bad way to spend time, though.