A companion book to The Breathing Book, Flow Studies contains easy phrasing exercises designed to help you learn breath control. It's really a sort of capstone to The Breathing Book in that it utilizes the knowledge you gained from The Breathing Book in order to improve your phrasing.
The guideline throughout Flow Studies is to play each phrase in one breath. There are no dynamics or tempos because you are encouraged to experiment with those attributes in order to learn breath control.
The phrases move through the range of the instrument in a systematic fashion, allowing you to examine the difference in your air flow needs relative to range.