From the Foreword, by David Baldwin:

Here is a trumpet book that has been waiting 90 years to become a classic in the advanced trumpet etude repertoire. David Bertie has taken on the monumental task of completely re-imagining every aspect of this work. Aaron Harris first published this series of violin studies and technical calisthenics in 1930. While an impressive body of work, it has never become widely used by trumpet players because of its many shortcomings.

…With David Bertie’s superb...