(Amadeus). The Opera Companion has established itself over the years as a classic reference book for opera lovers, whether devoted or casual. Synopses of 47 of the most frequently performed operas (18 composers) are given with key words to clue the listener in to the action and musical descriptions designed for those who cannot read music. A catalog of major operas lists composer, librettist, and date and place of first performance. It explains the techniques of opera in chapters on the overture, melody, aria, and recitative, with a description of the human voice as both an artistic and mechanical instrument. The book also includes a short history of opera, told chiefly in terms of the audience and its behavior, and offers a glossary to be read for enjoyment as well as information.