This is a good attitude for learning. Needless to say, Potts presented an abundance of information that I did not know. Some pilots treat their aviation books like prizes, placing them on their library shelf like a big-game trophy, to be looked at, but not touched. A book is a tool for learning, to be marked up where there is a valuable lesson or important fact that can be reviewed later. Writing in the margins is not taboo.
Books are to be used.
My copy of Potts' book is marked up more than most of my books. It is a usable and valuable tool in my library. I hope so. Used by permission.