A libretto is body of words used in an extended musical work such as an opera, operetta, oratorio, or musical. It includes the lyrics to the musical numbers as well as any spoken passages. The word libretto comes from Italian, and means "little book."
The role of the libretto in the creation of a musical work varies. Some composers, notably Richard Wagner, wrote their own libretti. Others adapted the libretto from an existing play (as Alban Berg did with Georg Büchner's Woyzeck), or had this done for them, as with Francesco Maria Piave, who adapted works by Victor Hugo, the Duke of Rivas , and others. The works of William Shakespeare inspired many composers, including Purcell, Gounod, Verdi and Britten. Goethe's Faust also spawned a large number of opera adaptations.
Metastasio (1698-1782) (real name Pietro Trapassi) was one of the most highly regarded librettists in Europe. His libretti were set many times by many different composers. Another noted 18th century librettist was Lorenzo da Ponte, who wrote the libretto for three of Mozart's greatest operas. Eugène Scribe was one of the most prolific librettists of the 19th century, providing the words for works by Meyerbeer (with whom he had a lasting collaboration), Auber, Bellini, Donizetti, Rossini and Verdi. The French writers' duo Henri Meilhac and Ludovic Halévy wrote a large number of opera and operetta libretti for the likes of Jacques Offenbach, Jules Massenet and Georges Bizet. Arrigo Boito, who wrote libretti for, among others, Giuseppe Verdi and Amilcare Ponchielli, composed two operas of his own.
Many writers of libretti have been sadly overlooked in the receipt of credit for their work. Certainly some were recognized as part of famous collaborations, as with Gilbert and Sullivan. However, in many other cases the composer of the musical score to an opera or operetta has been given the lion's share of credit for the completed work, and the writer of the lyrics relegated to a mere footnote. In some cases, the opera adaptation became more famous than the literary text on which it was based, as with Claude Debussy's Pelléas et Mélisande after a play by Maurice Maeterlinck.
On the other hand, the affiliation of a poor libretto to great music has sometimes given the libretto's author a kind of accidental immortality. Certainly it is common for works of classical music to be admired in spite of, rather than because of, their libretti.
- Public-Domain Opera Libretti and Other Vocal Texts