The composer's last masterpiece and the third of his three Shakespeare operas, Falstaff is also Verdi's only comedy. He was not renowned for a rollicking sense of humor, and after receiving a libretto by Arrigo Boito based on one of Shakespeare's most perishable farces, The Merry Wives of Windsor , he set about adapting a subject that would seem to have been alien to someone who had written so feelingly about revenge: the humiliation of the lovable old Elizabethan scoundrel Sir John Falstaff by a gaggle of silly, suburban matrons.

With astonishing resourcefulness for a man approaching 80, he gilded Boito's relentless buffoonery with his most richly mercurial score, producing an opera that is as easy to admire for its musical inventiveness as it is to resist for its emotional heartlessness. At least on opening night, the Met's production, which is a refurbishment of the Franco Zeffirelli staging at the old Met in 1964, seemed determined to bring out all the heartlessness it could.

Visually, the Zeffirelli production, whether it's in the half-timbered interior of the Garter Inn or Ford's sunlit garden, remains serviceably picturesque. But Falstaff , with its torrential flow of dialogue, declamations and ensembles, requires a director's deft touch in myriad ways if it is not to come across as a strenuous exercise in tomfoolery. Mr. Zeffirelli chose to stay in Italy and leave the hands-on work to assistants-and it showed.

Falstaff's thieving sidekicks, Bardolph (Jean-Paul Fouchécourt) and Pistol (Raymond Aceto), were stock ruffians. The lovers, Nannetta (Camilla Tilling in a gorgeous Met debut) and Fenton (a sweet but underpowered Gergory Turay), cut good-looking figures but seemed weirdly disconnected from each other. Dwayne Croft's Ford was another of this fine baritone's woodenly grandiloquent performances; and the three merry wives (Marina Mescheriakova's vocally insecure Alice Ford, Stephanie Blythe's richly eloquent Mrs. Quickly, and Susanne Mentzer's wackily unfocused Meg Page) seemed so competitive in their mugging and mincing that a friend was moved to remark that they should be called the hysterical wives of Windsor.

Musically, the greatest glory of Falstaff is its orchestra writing, which assumes a brilliant theatrical life of its own. In the booklet for an excellent new recording of the opera on Deutsche Grammophon, the conductor, Claudio Abbado, writes that "the orchestra itself seem to be laughing." Under the direction of James Levine, the Met's orchestra more often seemed to be grimacing; every interjection by the woodwinds or the cellos was like something out of Shakespeare for Dummies , and what should have sparkled thundered. Mr. Levine's sense of comic pacing is sometimes elephantine-his Meistersinger last fall was painfully slow-and on opening night this fleetest of operas moved with a remorseless tread. (Most infuriatingly, the Met, with its customary lack of concern for one's bedtime, stretched what should have been a delightfully swift evening-the opera itself runs a little less than two hours-into an interminable one that lasted nearly three and a half hours, thanks to two endless intermissions and protracted pauses for scene changes in Acts II and III. Are ordinary operagoers being made to suffer for the indulgence of the patrons lingering over mediocre, excessively priced food in the Grand Tier Restaurant?)

Fortunately, there was Mr. Terfel. A few days earlier, I had heard the strapping Welsh bass-baritone in a recital at Carnegie Hall, where I was struck anew not only by his familiar rugby-player-next-door charm, but by his voracious musical intelligence. Beautifully accompanied by his longtime pianist Malcolm Martineau, Mr. Terfel strode from Schubert to Vaughan Williams, Duparc, Copland and the young American composer Jake Heggie (the American premiere of a rather wan cycle of Vachel Lindsay poems entitled The Moon Is a Mirror ) with an easy intensity appropriate to each composer and a range of vocal colors that could turn from terror to tenderness in a single breath. Hearing Mr. Terfel as nothing but himself is terrific entertainment; hearing him as the Shakespearean rogue knight is great theater.

Verdi and Boito shrewdly chose to incorporate the more resonant Falstaff of Henry V into their adaptation, and no performer in my memory traces the character's journey from the titanic hedonism of Act I to the self-delusions of Act II to the vulnerability of Act III more powerfully than Mr. Terfel. Not even his outsize tummy prevents him from prowling the stage like a ferociously territorial fox. (Watch that foot dart forward in the first scene when he trips Pistol into a pratfall.) As the prospect of winning the heart of Alice Ford dawns on him, Mr. Terfel manages to radiate both a palpable glow and, more subtly, the sense that he is having doubts about whether he's really up to a roll in the hay. His most telling stroke comes at the beginning of Act III. Having been unceremoniously dumped into the Thames in a basket of dirty linen, he is seen climbing laboriously out of the orchestra pit. As Mr. Terfel hauled his prodigious bulk onto the stage, you felt that he was spending every last ounce of himself. When he sang of the unfathomable wound to his pride, he seemed as small as a whipped child. But as he realized that he was back outside the good old Garter, with its ready supply of wine, you could feel the life force seeping back into him, until he was once again Jack Falstaff-still unconscionably outrageous, but now, like Lear, a little wiser.

Not to worry. I made the trek out to Cooperstown on the second weekend in July, and on the basis of the first two productions-Verdi's Falstaff and Puccini's Tosca -I can report that the "Glyndebourne of America," as Glimmerglass has been dubbed, is in as good, if not better, shape than it has ever been. I don't know of too many other small opera companies that could survive the last-minute loss of the baritone who was to sing Sir John Falstaff and the tenor who was slated for Mario Cavaradossi in Tosca , but Glimmerglass has become such a prime proving ground for America's best young singers that the emergency was handled with dispatch.

Certainly, the Falstaff of Mark Delavan, who joined the cast just two weeks before rehearsals, promises fine things for this young American baritone. I had admired the open-door roominess of Mr. Delavan's voice-so reminiscent of the great American Verdian of the 40's and 50's, Leonard Warren-in the title role of last season's Macbeth at City Opera, but had found his acting a bit blocky and unshaded (or perhaps too shaded, given the fact that he was up against the take-no-prisoners Lady Macbeth of Lauren Flanigan). The antihero of Verdi's final opera, which fuses the cunning Falstaff of Henry IV with that of the grand sybarite who gets his comeuppance in The Merry Wives of Windsor , can easily degenerate into a generic buffoon-a wearisome dirty old man. Mr. Delavan's Sir John, all done up in splendid disarray, was richly imposing but never merely grotesque-a bull who threatened, but never succeeded, in demolishing the intricate clockwork of this most delicate of operatic romps.

Indeed, Leon Major's production, with sets and costumes by John Conklin, is one of the cleanest, most fluent stagings of Verdi's last will and testament that I have ever seen. Falstaff is not an opera that encourages "revisionist" interpretation. As with the other two members of opera's trinity of comic masterpieces, The Marriage of Figaro and Die Meistersinger , all of its parts are so thoroughly integrated into the whole as to defy tampering with. All Falstaff needs is to be presented -clearly, deftly and with immense affection. Mr. Major, the artistic director of Boston Lyric Opera, must have had Falstaff in his bones for a very long time, for his coordination of the very busy goings-on in and around the Garter Inn-the posturings and plottings, the maskings and unmaskings, the furtiveness and ardor-is absolutely seamless, as inevitable and logical as the most naturally surreal Buster Keaton comedy. About Mr. Conklin's stage designs I have nothing to say except that they are utterly appropriate-picturesquely cluttered where clutter is the essence of things (Sir John's debauched lair), elegantly simple where elegant simplicity is required (Fenton's moonstruck aria).

Falstaff , perhaps more than any other opera, rises or falls on the alertness of its ensemble, both onstage and in the pit. Listening to the exquisitely pell-mell effects that George Manahan, the conductor, achieved with his forces, I felt I was in the presence of a seeing-eye cat. Mr. Manahan's intelligence seemed to be everywhere at once in this Halley's comet of a score-not by pushing it or pulling it along, but by pouncing on its every felicity so tellingly that each flash of melody played its just part in the continuous, magical flow. Among the evenly superb cast, I was especially taken with the robust Ford of Stephen Powell and the vivacious Alice of Amy Burton, who more than fulfilled Verdi's injunction that she be played as though she has "the devil in her."

The fact that the pivotal role of Baron Scarpia in Tosca was a colorless, stock Italian baritone named Michele Bianchini did not, surprisingly enough, lessen the visceral power of Mark Lamos' new production of Puccini's pulpy study of sexual cruelty. With his customary facility for getting to the essence of things and bringing them out with stylish vividness, Mr. Lamos has updated the story's lurid events to Mussolini's time, with a minimal set, by Michael Yeargan, featuring an overhanging, malevolent cross that would not be inappropriate for a new S&M club in Chelsea. At the Sunday matinee I attended, Glimmerglass' music director, Stewart Robertson, drew an unusually charged performance from the young musicians in the pit, one that was unblushing in both bombast and tremulousness.

And if the last-minute Mario Cavaradossi of Ian DeNolfo was as woefully short on any sense of a musically shaped line as he was long on a genuine tenorial ring, that didn't matter much. Tosca succeeds or fails largely on the strength of its leading lady, and in Amy Johnson, a City Opera stalwart to whom I have not paid enough attention, it has a stunner. Dressed magnificently, by Constance Hoffman, in floppy hats and soigné , 30's-style deco dresses out of a Tamara de Lempicka portrait, Ms. Johnson, who possesses a beautifully pointed soprano, was as alluring a Tosca as I have seen since the last days of Maria Callas at the old Met. Coiled yet fluid, vulnerable yet implacable, she would, in the old days, have been swept off to Hollywood by the likes of Josef von Sternberg. Fortunately, she is being swept off to the City Opera's mounting of this Tosca at the New York State Theater in September, where she is certain to bring down the house.