You need to read it in a context where there is nothing else to do, and you can leisurely let your thoughts move between the book and your life.
Read in this way, the book can act as a catalyst for meditative insights -- overlooked possibilities, bigger pictures, new roles and options, and alternative directions for the future.
I find certain books required a deep thought before you can get anything out of it. These books aren't something that you can read in a plane on the way to New York from LA.