Arrigo Boito was an Italian librettist, composer, poet and critic whose only completed opera was Mefistofele. Among the operas for which he wrote the libretti are Giuseppe Verdi's monumental last two operas Otello and Falstaff as well as Amilcare Ponchielli's La Gioconda.

A libretto is the text used in, or intended for, an extended musical work such as an opera, operetta, masque, oratorio, cantata or musical. The term libretto is also sometimes used to refer to the text of major liturgical works, such as the Mass, requiem and sacred cantata, or the story line of a ballet.