The libretto is typically written by someone other than the composer.
Librettos of the Great Operas.
Gary D. Schmidt -- Okay for Now
Don Giovanni was playing on the car radio—Nathan knew the libretto by heart, he sang very good opera Italian—and he joined in and sung at the top of his voice and got so wound up in the whole opera that he missed the turn to Brooklyn College and goes all the way down Flatbush Avenue practically to the ocean.
William Styron -- Sophie’s Choice
Then her remembrance of the novel helping her to understand the libretto, she followed the story phrase by phrase, while vague thoughts that came back to her dispersed at once again with the bursts of music.
Gustave Flaubert -- Madame Bovary
To talk at great length with very minute details, of persons in whom they took not the slightest interest in the world; another proof that in that ravishing opera called love, the libretto counts for almost nothing; For Marius, to listen to Cosette discussing finery; For Cosette, to listen to Marius talk in politics; To listen, knee pressed to knee, to the carriages rolling along the Rue de Babylone; To gaze upon the same planet in space, or at the same glowworm gleaming in the grass;…
Victor Hugo -- Les Miserables
…always alike, filling all my nights and days, differentiated this period in my life from those which had gone before it (and might easily have been confused with it by an observer who saw things only from without, that is to say, who saw nothing), as in an opera a fresh melody introduces a novel atmosphere which one could never have suspected if one had done no more than read the libretto, still less if one had remained outside the theatre, counting only the minutes as they passed.
Marcel Proust -- Swann’s Way
All the English authorities that I have had access to advocate retaining the foreign plurals of most of the foreign words in daily use, /e. g./, /sanatoria/, /appendices/, /virtuosi/, /formulae/ and /libretti/.
Henry L. Mencken -- The American Language
She came in the morning, stayed till lunchtime, and for two solid hours bored me reading out that gibberish-a libretto in verse by the Symbolist A— to the cosmogonic symphony by the composer B— with the spirits of the planets, voices of the four elements, etc., etc.
Boris Pasternak -- Doctor Zhivago
It’s a terrific libretto," allowed Holland, a slow smile breaking across his face.