In the introduction to “Corners” Allan Colin writes: “If you glance through these pages, do not be fooled by the diatonically simple configuration of notes. The challenge here lies in doing these exercises from top to bottom exactly as specified. The goal is to strengthen weak corner muscles which plague many trumpet players.

In your effort to accomplish this it is imperative not to overdo it. As with any practice session where you are trying to straighten out a problem, the “warm-up” and “wa...