From the material: "The way in which the player can control the sound of a brass instrument with the lips is fascinatingly complex and not scientifically understood fully." This course completely ignores the fact that the tongue level in the mouth and the pressurization of air are both involved in tone production and manipulation. This is a serious flaw. Principles of air dynamics should be discussed, at least peripherally (and this has been studied extensively in many instruments, not just brass). If you weren't a brass player, you'd leave this course thinking that all brass players do is buzz their lips to play their instruments. If you're interested in learning more, look at the trumpet instruction books by Claude Gordon. Generally, this is a very superficial and disappointing treatment of the material.