Systematic Approach To Daily Practice was the first book written by Claude Gordon. It is much more than range studies, even though the exercises are written to Double High C and down to Double and Triple Pedal C. The book is unique as perhaps the first book ever to show how an average player can develop playable range with high notes to Double High C and even Triple High C. Even more significant is that this book shows how to practice. It has 52 weeks of example practice routines that combine the use of other great method books. This truly shows the genius of Claude Gordon's teaching and is still unique to this day. This shows how to develop practical skills to be a working trumpet player with a long career.
The other books referred in the example practice routines are as follows:
Herbert L. Clarke's Technical Studies
Walter Smith's Lip Flexibility
Saint-Jacome's Grand Method
Charles Colin's Advanced Lip Flexibility Studies
Herbert L. Clarke's Characteristic Studies