Tosca The challenge of the title role in Puccini's Tosca, from where I sit, is to make a human being out of this collection of acting-class exercises ("OK, now show me...jealousy! Go!"). If the soprano doesn't manage that, the show can still be a lot of fun; Puccini's luscious, explosive music and impeccable theatrical sense ensure it. But a Tosca can hit every high note, both literally and metaphorically, and still leave open the question of what on earth her lover, Cavaradossi, sees in her—and, therefore, what should we. Lisa Daltirus, who sang the part opening night, gets an A for Murderous Rage and Supplication—she's affecting in "Vissi d'arte," her why-do-bad-things-happen-to-good-people aria—but maybe needs some remedial study in Coquettishness and Imperiousness. Uninhibited but not seductive, hot-blooded but very rarely charming, she was at her best in the second act, her showdown with the villainous police chief, Baron Scarpia. Cavaradossi, whom Scarpia is using as a pawn—first to find an escaped political prisoner, then to get at Tosca herself—is sung by Frank Porretta. His voice is a strong tenor of no striking color, attractive in lyrical melodies and secure in the frequent moments he chooses to milk (during his cry of "Vittoria!" in Act 2, you practically had time to pop out to the lobby for an espresso). There's no unpleasant strain in those high notes, but you can definitely hear the muscle behind them—a display of vocal athleticism that's exciting in its way, and definitely impressive, but which seems to distract from the emotional point of the moment. A master of ambiguity, baritone Greer Grimsley is unbeatable playing men with a dark side (Wotan, the Flying Dutchman, or the sheriff from The Girl of the Golden West). Scarpia, of course, has more than just a dark side, he's loathsome to the core. But you can count on Grimsley never to settle for two-dimensionality; he gives Scarpia a black-velvet suavity, making him magnetic enough so that we're complicit in his evil. It's the ultimate manipulation in this most manipulative of operas. Director Chris Alexander trusts Puccini enough to leave Tosca alone; his production is traditional to the last trompe-l'oeil stone in Thierry Bosquet's set, and makes no false steps.