Louis Vierne’s “Carillon de Westminster” from the Troisième Suite, opus 54, of his 24 Pièces de Fantaisie is a favorite of organists and audiences alike. While many play this piece, how many take the time to study the unique harmonies in this music? Organists view Vierne’s compositional style as highly chromatic. Yes, this is certainly true. However, how does one analyze Vierne’s music?