Why you should read this...
Mr. Adam recommended students read this book, because it examines mastery of a craft. While we might think of ourselves as being smart enough to control all the motor functions in our body to produce a result such as shooting an arrow to hit the target or play the trumpet to hit that note, there is far more to it than focusing merely on a set of instructions for position and movement. When the master demonstrates to his student how he was able to hit the target in the dark, he credits that "It" shot the target. There is no element of mysticism of what "It" is referring to. The archer has in his mind the target and through many hours of practice over a period of time, he is not thinking of the mechanical movements to achieve desired results. "It" is the macro summation of the goal of all your efforts.
When you play trumpet you focus on the most beautiful sound you can imagine and that is your "It". We are not robots who can take a set of complex instructions and provide an immediate result. This comes from a purposeful attention to the goal, and that is achieved by productive practice. This is why in each trumpet lesson, Mr. Adam would always lead the student by playing on the trumpet as an example of what the student should sound like. This is the goal, and too easily our minds can get distracted from the goal. Having a weekly lesson with Mr. Adam to get a reforcement of that sound was paramount to a student's success.