I vespri siciliani = The Sicilian Vespers : an opera in five acts : in Italian and English / the music by Verdi : as represented at the Royal Italian Opera, Drury Lane.

Original French libretto by E. Scribe and C. Duveyrier. Cf. New Grove dictionary of music and musicians.
The text is in Italian and English in parallel columns.
T.p.: p. [1]; "Dramatis personae: p. [2]; "Argument": p. [1]-[2] (2nd group).
The singers listed under "Dramatis personae are: Mademoiselle Titiens, Mademoiselle Dell'Anese, and Signor[i] Mercuriali, Corsi, Annoni, Vialetti, Fagotti, Castelli, Ponti, and Mongini.
Probable first edition for the first London performance of the opera (27 July 1859).