Treatise On Harmony -

: He was the first to formalize that a chord like is the same entity as

: Rameau argued that every chord has a "root" or fundamental note, regardless of which note is in the bass. This allowed for the identification of a core harmonic identity. Treatise on Harmony

: Focuses on the practical art of playing from a figured bass on instruments like the harpsichord or organ. Availability and Modern Use Treatise on Harmony (Dover Books On Music: Analysis) : He was the first to formalize that

. Before this, theorists viewed these as entirely different intervals above a bass note. Availability and Modern Use Treatise on Harmony (Dover

The treatise is divided into four distinct books that move from abstract math to practical performance:

: Introduces the practical application of his theories, explaining the fundamental bass, modes, and the rules governing chords.