First I assume we are talking about recorded opera (most opera on DVD bores me, too static, though many swear by it), but of course go live when you can. My core view is that people "do well" with culture when they feel they are in control, and tune out otherwise. So pick one area and master it, or at least get intrigued, rather than trying to survey all of opera. Those "introductory" books are probably counterproductive, if only because they let you know how much ground there is to cover. Who could possibly master five different recordings of Parsifal?
Here are a few areas to start with:
1. Mozart: Get Abbado’s Magic Flute (a new recording, truly splendid, one of the best of 2006 or any year), the Rene Jacobs Figaro, and the Colin Davis Don Giovanni. If you love those, move on to Cosi Fan Tutte and then Beethoven’s Fidelio.
The Ingmar Bergman film of Magic Flute is perhaps the single most inspiring introduction to opera, even if they are singing in Swedish. It is cinematic in conception, rather than a mere film of a performance, thus avoiding the DVD problem.
2. Italian opera: Start with Rossini’s Barber of Seville, Gobbi/Callas, then either Verdi or Puccini, in the former case La Traviata (many good versions) or Aida (Karajan), in the latter case start with La Boheme (Beecham). Move out into Donizetti (The Elixir of Love, bubbling and playful erotic fun) and the rest of Verdi, culminating in Otello and Falstaff, his greatest and deepest works, no organ grinder music there.
3. Wagner: Go for some extended excerpts, most notably Kempe’s one-disc condensation of Das Rheingold (better than the full-length version), this four-disc set of scenes, or Act One of Tristan und Isolde, by either Karl Boehm or James Levine. Work up to Parsifal or Valkyries, but in my view Act One of Tristan was his peak and this remains music’s greatest erotic/death-wish experience, so good it is dangerous, maybe you should just stop reading this blog.
If you are putting on four discs of Flying Dutchman, Tannhaeuser, or Goetterdaemmerung, and hoping to make sense of it, your planning has gone badly wrong.
4. Twentieth century: Start with the fun, accessible works, like Glass’s Einstein on the Beach, Robert Ashley’s Improvement, or Michael Nyman’s The Man Who Mistook His Wife for a Hat. Over time head to Stravinsky, Schoenberg, Ligeti, Messiaen, Lachenmann, Mercury/May and many others.
If you want to leap into the unique and the complex, consider Monteverdi’s Orfeo, Tchaikosvky’s Queen of Spades, Strauss’s Capriccio, or Debussy’s Pelleas and Melisande. Liszt fantasies and transcriptions are a good entry point into opera, that is how I got my start, his Robert de Diable Meyerbeer transcription (played by Earl Wild, among others) has to be heard to be believed, same with his Norma fantasy, after Bellini.
Arguably Bach’s St. Matthew’s Passion is the greatest opera of them all, but that is another story.
By the way, few of the libretti are worth knowing beyond a plot overview; Don Giovanni is a notable exception, Der Rosenkavalier is another. Keep in mind that a lot of opera simply isn’t very good. The biggest problem is too much filler, even in the true classics. Don’t let these boredom traps keep you away from some of music’s highest peaks.