But as Sondheim and his collaborator Hal Prince were fond of saying in the 1970s when it first appeared, Night Music was meant to be whipped- cream with knives; and the problem it has posed ever since is how to make the knives cut. In Sean Mathias's new production at the National (see also theatre review, page 14), they don't - even though Mathias has made concessions to sharpness like reviving Charlotte's abrasive "My Husband the Pig", dropped at the rehearsal stage of the original Broadway showing. What you get is a soft spectacle that spreads itself thin across too big and too open a space (the proscenium-less Olivier) where the action and a lot of indifferent choreography look lost.
The choreography is critical - because Night Music is largely a dance score and an exercise in triple time, indebted to the dark nostalgia of Ravel's La Valse which Sondheim must have absorbed intravenously as he was writing. At the National the only thing that dances with an ounce of virtuosity is the stage, which sweeps one scene into another with a sleek display of hi-tech transformation (a revolve that spirals up and down) but doesn't give much sense of time or place or atmosphere. Apart from its adroit mobility, the set is sterile, with a crossword-clue approach to telling you that you're in fin de siecle Sweden. Worse still, it gets veiled behind a gauze tube that descends like a capacious condom from the fly: a nice reminder of the risks of promiscuity (Night Music is an elevated sex-romp after all) but otherwise redundant.
So, not many points for presentation. But one of the fascinating things about Night Music is that for all its pull toward swirling ensemble numbers, the substance of the piece decants into solo songs that address the audience face on. Everything ultimately hangs on individual performances - which, at the National, are class acts even if they come with no more voice than absolutely necessary. Patricia Hodge is a joy as Charlotte, the wife who poignantly accommodates her husband's infidelities: a text-book illustration of how Sondheim's genius flowers in the subdued compromises of real life rather than the exuberant triumphs of fiction. Sian Phillips is a chilly Madame Armfeldt but delivers her set-piece song "Liasons" with the right degree of faded spice. And Judi Dench plays Desiree like it was one of the great character roles of modern theatre - as maybe it is - with an endearing shabby grandeur and incredible finesse.
Above all, these are performances that celebrate the sheer refinement of a piece that makes its points through eloquence rather than body-blows. Night Music isn't flawless: I'm never really convinced by the usefulness of the liebeslieder chorus or the sudden escalation of activity in the denouement. But as an essay in the interaction of time, love and human frailty it raises the stakes of musical theatre beyond the compass of any other composer I know writing today. And in "The Miller's Son", "Every Day a Little Death" and, of course, "Send in the Clowns", it has three songs which are the equal of anything in Sondheim's output. Which is to say, the equal (at least) of any theatre-music going.
Franco Zeffirelli's production of Tosca has been going for more than 30 years at Covent Garden, re-staged by John Cox but with the same designs; and in that time it has been a sort of hotel de passe for celebrated divas - starting with Callas (whose ghost still haunts the sets) and including Bumbry, Caballe and Behrens. Now the plum-velvet dress has passed to Galina Gorchakova, whose recent appearances at the Edinburgh Festival raised doubts about whether she was in sufficient vocal shape to tackle such a heavy role. As things have turned out she seems back on form, and that cream-covered tone, opening to a compelling top, is sounding full and beautiful again. But I don't think that Tosca is her role. She stands out from a not-so-special cast at Covent Garden, but the sense of focus comes and goes. She doesn't live the character from start to finish, and she isn't noticeably Latin. There are operas better suited to her voice and personality.
Also down from Edinburgh have been Peter Schreier and Andras Schiff, repeating at the Wigmore Hall the Schubert song-cycle series they gave in the Festival a month ago. Schreier and Schiff are a glorious affront to the idea of voice and piano duos as unequal partnerships. And although Schiff is the most attentive of accompanists - so attuned to every gesture of his singer that they feel like dancing partners - he is a pianist of such distinctive stature that there were times during Die Schone Mullerin when the interest of the piano part eclipsed the voice. Like Britten, Schiff plays Schubert with a near-orchestral range of colour, sensitive and "literate" in the immediacy of its response to text. I can't quite say the same for Schreier, whose lieder singing these days is detached: more the sophisticated raconteur than the engaged participant. And the voice, alas, is showing signs of age: forced at the top and harder than five years ago when he recorded Schone Mullerin with Schiff for Decca. But for all that, Schreier is an artist of authority: a Meistersinger whose immersion in the repertory carries persuasive force.
I suppose it was the Peter Schreiers of the podium whose shadow kept Simon Rattle away from the core Viennese classics for so long. Rattle made his name with modern scores and has been coyly holding back from Beethoven until the time seemed right. But now he is embarked on his first Beethoven Symphony Cycle, running in Birmingham and London with the CBSO; and from the first instalment of Symphonies 1 & 3 there can be no doubt that the time is right. His readings are a strong, coherent synthesis of period sensitivity with Grand Tradition. They feel thoroughly absorbed but at the same time brilliantly alive, with an exhilarating rhythmic ardour and a crystal clarity of sound throughout the orchestra - which Rattle realigns in recognition of the disparate demands of these two scores. For No 3 he has more second violins than firsts and the same number of basses as cellos, which is something to think about.
As often with Rattle's CBSO performances, I'm tempted to qualify my enthusiasm with the rider that it was remarkable in spite of the limitations of the orchestra (especially the string sound). But with Beethoven's Third it's not inappropriate to feel that the instruments are being stretched to their limits. Like hearing Beethoven sonatas on a fortepiano rather than a Steinway, you're reminded of the challenge that the music set its first interpreters. And that's exciting.
'A Little Night Music': Olivier, SE1 (0171 928 2252), in rep. 'Tosca': ROH, WC2 (0171 304 4000), Thurs. Beethoven Symphony Cycle: Birmingham Symphony Hall (0121 212 3333), 11 Oct; Barbican, EC2 (0171 960 4242), 13 Oct.