I recently watched (on a plane so only semi-voluntarily) the movie Perfume. A movie with interesting moments. I was intrigued by Dustin Hoffman's character describing the makeup of perfune. There is the head note which is what you first smell, then the heart note which makes up the core of the scent and then the base note which is what lingers with you.
I was left wondering whether something similar worked with a book. Does a great book leaves a base note - something indefinable, buried deep within the telling of the book, which only comes out over time, sometimes long after the book has been finished.