Maximum Power XL That is why I recommend you to make it your bedside book! In any case, this book should find a place in your library. As author Louis-Jacques Rondeleux says: "It's a practical book that helps us to accept that, even more than a vocal instrument, we are the ones we are building . ". If you are a coach or trainer, this method will be personally beneficial to you, and you will be able to draw exercise ideas for your students.