Ruggiero Leoncavallo tells us that his most successful opera I Pagliacci was accepted by the publisher Sonzogno after he had read only the libretto. Perhaps this was not so hasty and ill-considered a decision as, at first sight, it may appear, for a “book” as unfailingly effective as that of I Pagliacci is almost fool-proof; besides, a really dramatic libretto is a tremendous incentive to an imaginative composer. Triumphantly Bizet emerges from the slightly sentimental romanticism of his early operas the moment he receives Daudet's moving Arlésienne and, shortly afterwards, the spectacular libretto of Carmen. Moreover, we have only to note how Verdi's powers soared when, in his extreme old age, they were stimulated by Boito, a librettist at last worthy of his great collaborator's genius.