Wagner’s Parsifal stands alone in the operatic canon. No other opera is so fraught with interpretive perils, so encumbered by tradition, so undermined by preconceptions as this one. Wagner called this work a Bühenweihfestspiel, a uniquely German term that can be variously translated as “stage dedication play” or “festival play for the consecration of a stage.” The appellation is significant because Parsifal was the only one of Wagner’s operas to premiere at his specially designed Festspielhaus in Bayreuth, in 1882. Indeed, Parsifal was composed with the hall’s sonic peculiarities in mind. Given that the opera was also, in effect, the great composer’s final testament (he died six months after its premiere), Parsifal has always been favored by Wagner cultists as the apogee of Holy German Art. (This term, which the composer explicitly celebrated in his penultimate opera, Die ...