The Definitive Kobbe's Opera Book

Now, after more than ten years, this famous work of the stories of more than 300 of the world's great operas has been entirely revised, updated, expanded, and reset in a manner zestfully responsive to the explosion of enthusiasm for opera over the last decade.

There are lots of books that detail operatic plots, but this is the classic. It offers more than most such guides including historic background and musical examples of major themes. Now revised, this is a good first resource for the operagoer who wants to know exactly what s/he is going to see and hear.