Herbert L. Clarke's Technical Studies
Claude Gordon used to say that every trumpet player needs two things, Clarke's Technical Studies and good food. This is one of the most essential books that you will never outgrow. Each time through this book will yield more fruit as it develops finger dexterity and breath control and other refinements. It is loaded with concise pithy wisdom from Clarke. See my article entitled "Clarke's Technical Studies, Then and Now" about the original text vs. the later
The Bass Clef version was arranged by Claude Gordon with notation by William B. Knevitt.