The quality of any major opera company must be judged by the standard it achieves in its presentation of the Mozart-Da Ponte cycle of operas; in my opinion they are the bedrock of the repertoire. In Dallas, we have presented Figaro in Christopher Alden's 2002 production; we closed last season with Don Giovanni in Harry Silverstein's conception; and now, at Thanksgiving, we complete the trilogy with Cosí fan tutte, which, translated, means: "Thus Do They All" or "All Women Are Like This." (The other, lesser-known title of the opera is La scuola degli amanti or "The School for Lovers.")

What binds these pieces together is not merely the genius of Da Ponte and Mozart. Think for a moment how much more persuasive a dramatist Mozart had become since his Idomeneo of 1780 and, two years later, his Entführung (Mozart's first opera for Vienna), after which the Emperor pronounced his immortal verdict: "Too many notes, my dear Mozart."

Cosí fan tutte premiered at the Burg Theater in Vienna on January 26, 1790. The connecting thread is immediately apparent. Indeed, the very words, "Cosí fan tutte," have already been sung by Don Basilio in the opening act of Figaro‹music which is reprised in the overture of Cosí. The crucial thing to remember is that the events of Figaro, Giovanni, and Cosí all occur within a scant 24 hours. In Cosí, everything is pared down to the interactions of just six people. If there is a strong inner tension in the cast, we are in for one unforgettable evening of opera.

For those of you experiencing Cosí for the first time, all you need to know is that two couples are very much in love: Fiordiligi is engaged to Guiglielmo, Dorabella is betrothed to Ferrando. The two sisters are devoted to their sweethearts. A wise old cynic, Don Alfonso, offers the naive young men a bet that within a day, he can make the young ladies forget their lovers and look elsewhere for romance. The officers, full of youthful arrogant passion (and perhaps too much wine), take the confirmed bachelor's wager‹supremely confident that their sweethearts will remain faithful and chaste.

Before 24 hours have elapsed, Fiordiligi succumbs to the delights of Ferrando, and Dorabella‹even more speedily‹falls for the irresistible charms of Guiglielmo. In the greatest stage productions of this piece, I believe the truth is far more telling when a question mark is left hanging over the fate of the two young couples. I am equally convinced that at the end of this tortuous day, the characters go their separate ways, "sadder but wiser" for the experience.

The last character in the proceedings is the maid Despina, who is willing, even eager, to aid the machinations of Don Alfonso so long as she is adequately paid for her services. In a marvelous line loaded with double entendre, Despina tells Alfonso the "new" lovers had better be well-endowed (referring to their financial assets, among other things). Yet, in the end, even the clever maid cannot outwit and outmaneuver the crafty old bachelor.

This will be my fifth production of this extraordinary work. I've collaborated on Peter Hall's faithfully historic production, Richard Jones's outrageous cartoon setting of a miniature Vesuvius with a handful of rabbits, as well as memorably elegant productions by John Cox (English National Opera) and Leon Major (Dallas Opera, 1992).

In a way, the simpler the production and the less acutely aware we are of sets and costumes, the better. So long as the stage lighting skillfully conveys the passage of those critical 24 hours.

Ultimately, the constancy of these two girls and their absolute trust in the men to whom they are engaged is what counts; a lesson made all the more dramatically apparent when they suddenly switch their affections.

Listen carefully to the opening 14 measures of the overture: There is a military call to attention before a solo oboe begins to weave its magic spell. The oboe, for me, in Mozart operas, portrays feminine truth, so perhaps the first phrase evokes Fiordiligi's honesty, the second phrase, Dorabella's faithfulness. The lower strings creep in, followed by a delicious feminine suspension‹a sort of 18th-century Tristan moment, as we hear the Cosí fan tutte theme, a silence, and then an orchestral explosion that fairly shouts, "COSÌ FAN TUTTE."

It is as if Don Alfonso, the experienced friend of the two young gentlemen, says, "All girls are like that," and, in the silence, reads the incredulity on the youths' faces prompting him to repeat, "No, really. Your girlfriends are not trustworthy."

We've either accepted the musical premise or not as we find ourselves transported by the orchestra‹presto‹into the wonderful, frenzied world of Naples, Italy, the beauty of its scenery and the ever-present threat of volcanic violence from Mount Vesuvius. A decade after this opera was composed, famed British Admiral Horatio Nelson would embark on his torrid, world-shaking, love affair with Lady Hamilton in this very city!

The manner in which the young ladies change the object of their affections is a source of endless fascination. Early on in Act Two, Guglielmo turns on the charm as he offers Dorabella his heart:

"Un core: e simbolo di quello ch'arde languisce, E spasima per voi." ("A heart: a symbol of that which beats within me and languishes for you alone.")

Dorabella, the more flirtatious of the two sisters, readily accepts. She does so with a speed that Guglielmo finds disconcerting; for if Dorabella has changed her affections so easily, Guglielmo reasons, his beloved Fiordiligi might be just as vulnerable to Ferrando's advances. Guglielmo sings the duet and finishes the scene with great romantic bravura, thoroughly enjoying the caresses of one sister while brooding about the fidelity of the other.

Ferrando's seduction of Fiordiligi is considerably more problematic. In Act One, we hear the great aria, "Come scoglio." Like the well-known truck commercial, Fiordiligi's heart is "Like a Rock!" It's unmoveable. She is betrothed to Guglielmo and determined to remain faithful to him. That message remains fairly constant all the way through the second act, although she questions her fidelity in the aria, "Per pietà." Fiordiligi is no pushover; she won't allow herself to take part in a mere flirtation. If need be, Fiordiligi is prepared to follow her beloved onto the battlefield in the ultimate test of her loyalty. Suddenly, she encounters Ferrando‹in the throes of despair and threatening to commit suicide. The emotionally frazzled Fiordiligi finally succumbs to her new lover as Ferrando sings, "Volgi a me pietoso" ("Turn to me, in me you find a husband and a lover. My idol, do not wait any longer.")

Ferrando has achieved his goal of winning the girl's affections within a day. Yet in doing so, he discovers previously unsuspected passions within himself. Because Fiordiligi resisted so valiantly and because Ferrando is forced to rely on truthful, honest, patient love to woo and win her heart, rather than the instantly heroic style of Guglielmo (a macho Errol Flynn type), the battle of wits and wills has generated a deeper and keener sense of yearning.

I believe this couple is much more ardently in love than they ever thought possible, and it is these two who suffer most in the opera's closing scenes. The sense of betrayal as the plot unravels wounds Ferrando and Fiordiligi to the core. Listen to what happens as Fiordiligi collapses into the arms of her "new" lover‹the oboe returns with a wistful rhapsodic phrase and time itself stands still.

By 1790, Mozart at age 34 had written the three finest operas in the repertoire and had achieved greatness on his own terms. The world's most remarkable composer should have lived another 40-odd years and created many more masterpieces. But fate was indifferent to the wishes of future musicians and audiences‹there was only Tito and Zauberflöte and less than two years for Mozart's genius to flourish before his death. During this period, money worries became increasingly daunting:

To Michael Puchberg, December 1789: "If you can and will lend me 400 gulden…you will be rescuing your friend from greatest embarrassment."

To Michael Puchberg, February 1790: "I beg you, most beloved friend, to lend me a few ducats just for a few days if you can do so, as I have to settle a matter at once which cannot be postponed."

To Michael Puchberg, May 1790: "Ah! I must have peace of mind. But what worries me dreadfully at the moment is a debt to the haberdasher in Stefansplatz, who…is now demanding payment urgently and impatiently."

To Archduke Francis, May 1790: "I venture to apply for the post of second Kappellmeister."

Notice that the job he pleads to be considered for, isn't even the top job.

In spite of Peter Shaffer's play Amadeus, I don't believe Salieri murdered Mozart. What I do believe is that the Viennese Masons, as a group‹aided by other factions and accomplices‹poisoned the atmosphere in that aristocratic city against the composer so that his commissions fell off and pupils became increasingly rare, forcing Mozart to turn to enthusiastic supporters in Prague in order to get his next opera produced.

As for Cosí, its genius went unrecognized for more than a century. The humanity of the opera was mistaken for immorality, cuts became commonplace, and it took the championship of composer Richard Strauss in the early 20th century as well as the dedication of the Opera Festival of Glyndebourne, England, which staged a landmark 1934 revival, to verify Cosí fan tutte's rightful place in the canon of great operas.

This year's Opera America conference in St Louis opened with a keynote speech from my old colleague, the opera stage director Graham Vick. His two favorite operas, he told that audience of fellow professionals, are Fidelio and Cosí, indicative of a few simple truths: We are endlessly fascinated by the question of who and why we love, and forever moved by the triumph of love over tyranny and adversity.

We're attracted, we fall in love, we marry, we pledge our troth‹hoping that we're prepared to live up to our promises and make our actions match our words. In Beethoven's opera, Leonore's mature and steadfast love for Florestan will see her through every predicament, every challenge, providing both the strength and the necessary courage to save the man she adores. In the beautiful, volatile heart of Naples, Da Ponte's lovers‹so young and fresh to the world‹learn that, although flirtation is the established order of the day, it comes at a hefty emotional price.

So which is the nobler sentiment? Love or loyalty? With hand over heart, ask yourself, "How trustworthy are my affections?" And remember, Mozart knows.

Graeme Jenkins is music director of The Dallas Opera.