Over sixty years after his death in 1931, Vincent d'Indy is still a much misunderstood and maligned figure in French music. Previous biographers have left a portrait of the academic figure par excellence, who turned the seemingly inspired and selfless inspiration of his master César Franck into a cold and authoritarian pedagogical system. This new study re-examines the evidence, reveals a much more psychologically complex and turbulent character, and finds that d'Indy was a tireless propagandist for a spiritual revival of French musical civilization.