The great superstar arrangers Nelson Riddle, Mancini and Don Sebesky wrote great books leaving many questions unanswered.
Music is as knowable as science.
With ears, head and heart in the right place we can all create the gloriously beautiful. Before you enter, please be prepared to reject convention. Let your thought processes be your guide to professional leading musicianship. If you are a beginner How to read music. They are enharmonic.