This list, intended to reflect the Operatic Repertory, consists of the most famous and historically significant operas, arranged alphabetically by composer followed by city and date of first staged performance. Many splendid and under-appreciated masterpieces, aside from operatic curiosities, can be found in entries under the names of their individual composers.
In many opera houses this international repertory is supplemented by local standards. An American list, for example, would include George Gershwin's Porgy and Bess and Samuel Barber's Vanessa. A French list would not omit Delibes' Lakmé. Wagner's Rienzi and Berg's Lulu are missing. Skirmishing about any accepted canon tends to be most intense around the periphery. All the operas in this list are discussed in standard guidebooks, such as The Penguin Guide to Opera, ed. Amanda Holden, 1994.
Details of plot, anecdotes and history of composition and production, etc. are found in the operas' individual entries (linked). These lists are not complete: complete lists of composers' operas are to be found in the composers' individual entries (linked).