At just 34 years of age, Théodore Dubois became a professor of harmony at the Paris Conservatoire. Whilst much of his compositional works have disappeared from primary classical repertoire, his teaching has had a lasting influence. Having taught successful composers, including Paul Dukas, it is clear that Dubois' Traité D'Harmonie is well-informed.
This music theory study guide covers a considerable range of theoretical aspects, from the varying musical clefs to the use of pedal notes, as well many other harmonic devices with expertise. In the preface, Dubois explains the need for his book, stating that it fills gaps in harmonic theory exercises which preceding guides had missed. With no harmonic elements left out, this Théodore Dubois theory guide is necessary to accompany all music studies.