That was required reading at the conservatory I went to years ago. (Not by the teachers, among us classmates. We made everyone read that we interacted with)

Got to play with Kenny at a jam thing a decade ago. Absolutely amazing experience.

There is so much that I can extrapolate on this subject, but I believe the greatest hurdle for a serious musician is that after you master all the dexterity, independence and music theory, the biggest hurdle is your own fucking self.