Fétis' main theoretical work and the culmination of his conceptual frameworks of tonality and harmony is the "Traité complet de la théorie et de la pratique de l'harmonie" of 1844. This book has influenced later theorists and composers including Paul Hindemith, Ernst Kurth, and Franz Liszt. In the "Musik-Lexicon" of 1882, Hugo Riemann states that "to [Fétis'] meditations we are indebted for the modern concept of tonality…he found himself emancipated from the spirit of a particular age, and able to render justice to all the various styles of music." Though some other theorists, most notably Matthew Shirlaw, have had decidedly negative views, Riemann's assessment captures the two key features of Fétis' text. Though he did not coin the term "tonality," Fétis developed the concept into its present-day form. He claimed that ""tonalité"" is the primary organizing agent of all melodic and harmonic successions and that the efforts of other theorists to find the fundamental principle of music in "acoustics, mathematics, aggregations of intervals, or classifications of chords have been futile."