Homework: Let us suppose you have a pair of tickets to Jules Massenet's "Le Cid," which the Washington Opera will present with Placido Domingo in the title role for eight performances beginning Oct. 30. You would like to do a bit of homework before going to see it. Those who want full value for their opera tickets should read up on the plot, characters and historic background of an opera they have not seen before. And not many of us have seen "Le Cid"; this is its first American production in more than 90 years.

So you get a copy of the wildly popular "Ticket to the Opera" by Phil G. Goulding, flip to the index, and draw a blank. Among Massenet's many operas, Goulding finds only "Manon" and "Werther" worth discussion.

Look for Handel's charming little pastoral "Acis and Galatea," which will be done in concert form by the New Dominion Chorale next Sunday. Sorry; Handel was an opera composer comparable to Verdi or Wagner, but Goulding finds room only for his "Giulio Cesare"--which the Washington Opera will perform this season. His book is an entry-level treatment, full of lists and anecdotes, breezy and opinionated, directed as the author cheerfully admits, to "the unwashed." Those who believe opera companies should take a few risks on less familiar material will have to look elsewhere.

If money is no object, the opera reference work of choice is the New Grove Dictionary of Opera, four hefty volumes totaling more than 5,000 pages ($275 in paperback). The New Grove has thorough, satisfying articles on "Acis and Galatea" and "Le Cid"--not to mention thousands of other operas.

For those who can't or won't invest in the New Grove, an excellent alternative--reportedly out of print but worth hunting down--is "The Da Capo Opera Manual" by Nicholas Ivor Martin, production coordinator of the Lyric Opera of Chicago. It discusses more than 550 operas with the thorough, no-nonsense approach of a professional writing for colleagues but keeping the text within reach of amateurs. It has well-detailed discussions of "Susannah" (scheduled by the Washington Opera this season) as well as "Postcard From Morocco," now in production at the University of Maryland, both of which are praised but given only a few sentences by Goulding.

"Ticket to the Opera" is more useful for the top 100 titles, including "Hansel and Gretel," which will be done by Capital City Opera in December; "Rigoletto," which opens the Washington Opera season Saturday; and "Tosca" and "Otello," scheduled later in the Washington Opera season. There are also excellent discussions of these productions on the Washington Opera's Web page, www.dc-opera.org.

"Otello" is big this year; it has been playing at the Met and opened Virginia Opera's 25th-anniversary season in Norfolk and Richmond. Handel's "Rodelinda" (not in "Ticket to the Opera") is scheduled for Norfolk and Richmond but not for George Mason University, which will get "The Marriage of Figaro," "Turandot" and "Porgy and Bess," all discussed by Goulding.

"Ticket to the Opera" would be useful for most of the Baltimore Opera's season: "Don Giovanni," "La Traviata," "Tannhauser" and "La Boheme"--but not, remarkably, for "La Cenerentola."

Busy tenor: Placido Domingo has been shuttling back and forth between Washington (where he is the artistic director of the Washington Opera) and New York, where he is not only a star of the Met but also the proprietor of a busy restaurant. Between rehearsals for "Le Cid," he opened this month in the Met's production of "Otello" and is now in its "Cavaleria Rusticana" and "I Pagliacci."

Cabarets: Pianist Carlos Cesar Rodriguez broke his arm in an automobile accident and will be unable to play for about six months. As a result, the "In" series at Mount Vernon College had to cancel an Oct. 8 program of Spanish music, but it has bounced back with a series of concerts featuring some of its most popular cabaret performers: Joseph Perna and Milla Ilieva, tonight and Oct. 22; Ana Castrello and Debra Tidwell, Oct. 23; Sally Martin and Judy Simmons, Oct. 24.

AIDS benefit: A concert for people with AIDS held earlier this month at Foundry United Methodist Church raised more than $26,000. Added to the proceeds of previous concerts, this brings the Foundry music department's total contribution to almost $126,000.

Listen and learn: The Friday Morning Music Club and Smithsonian Associates are collaborating on a series of Tuesday evening programs titled "How to Listen to Chamber Music," combining lectures and performances and tracing the development of chamber music from its origins to the present.

Pianist Jeffrey Siegel begins his sixth season of "Keyboard Conversations," combining performance and discussion, tonight at George Mason University's Center for the Arts. Titled "Fiesta," the program will focus on Spanish piano music.

Visitors: A free, four-day mini-festival of Italian pianists begins today at the Kennedy Center's Millennium Stage. It is a small step toward what its promoters hope may become an international arts festival in the Washington area. Tonight's program, at 6 p.m., will present pianist Roberto Cominato in music of Scarlatti, Bach, Rachmaninoff and Ravel. Tomorrow, at St. Mary's College of Maryland, the Franz Liszt Duo (Franco Nicolosi and Vittorio Bresciani) will give a master class and perform Liszt's "Faust" Symphony. Tuesday, in Catholic University's Ward Hall, J.C. Parreira will play music of Liszt and Brahms. In the final concert, Wednesday at the Millennium Stage, the Franz Liszt Duo will play transcriptions of Wagner's operas.