"Salome" falls into the special category of "unpleasant masterpieces," but despite the famous (and thematically marginal) "Dance of the Seven Veils," which climaxes with 30 seconds of full frontal nudity in the Washington Opera's new production, "Salome's" purpose is not to entertain or titillate but to shock. If you can sit through it undisturbed, it isn't working.

Saturday night, with Maria Ewing in the title role and Gerard Schwarz in the pit, "Salome" worked. There were a few opening-night glitches, mostly relating to balance between voices and the orchestra, but the power that Richard Strauss packed into this opera came across with shattering impact.

"Salome" generates a special kind of horror, complex and intensely concentrated. It is expressed in physical terms -- above all, with the severed head of John the Baptist, which Salome caresses, kisses and lectures insanely in the opera's chilling final scene. But there is also the massive blade on the executioner's sword; there is the body of Narraboth, captain of the guards, whom Salome drives to suicide and who is left lying on the stage for much of the opera. In John Bury's fin-de-sie`cle stage design for this production, there is also the moon (a prominent symbol in the text as well), which moves across the sky as the evening proceeds, changing color and briefly disappearing at the opera's (literally) darkest moment.

Still, the real horror is psychological; "Salome" is about the beast that lies within each of us -- hungry, savagely self-centered and ready to pounce and punish the slightest affront. Usually, we keep the beast hidden, muzzled, not even acknowledged. But at the court of Herod around the year A.D. 30, Oscar Wilde's text would have us believe, people said -- indeed, shouted -- exactly what they felt; neuroses were treasured and displayed proudly to the world like family heirlooms.

Wilde lets it all hang out, and Strauss amplifies the effect with music that scorns traditional operatic melody and wields leitmotifs with a concentrated power that Wagner might have envied. Herod is a man torn between lust and fear, abused by a haughty, shrewish wife and insecure about his own authority, intimidated by the might of imperial Rome, which occupies his land, and by the ancient religious traditions he has abandoned but not really outgrown. His wife, Herodias, aging and resenting it, is driven by simple-minded pride, stung by the rebukes of the prophet, jealous of her daughter's youth and sexual power but willing to exploit it for her own purposes. John the Baptist, or Jokanaan, a wild man who has wrestled with God in the desert, now fears nothing human. He is eager to proclaim his harsh truths in the strongest words he can find, careless of the consequences and scornful of the ruling family that tries to mask its human weaknesses in pagan royal splendor.

At the center of these tensions is Salome -- young, beautiful, absolutely inflexible in going after what she wants, interested in testing the limits of her sexual power and willing to kill nonchalantly if someone offends her.

There is a kind of madness in this child that is powerfully conveyed in Ewing's performance: the madness of the solipsist who believes, deep inside, that nobody else really exists or really matters, that her will is the only meaningful reality and that her power is, or should be, unlimited. All this is communicated in the way she sings to the prophet's severed head: "Ah, you would not let me kiss your mouth, Jokanaan! Well, now I will kiss it! I will bite it with my teeth as one bites a ripe fruit!"

At first, it may seem that the chief problem of this opera is that it has no character with whom a normal, upright member of the audience can identify; the closest (and not very close) is Narraboth, the first of the evening's three corpses, who commits suicide when he cannot prevent Salome (whom he loves) from violating Herod's order and talking to Jokanaan. All the rest, including secondary characters, are fanatics, neurotics, people driven to one extreme or another. But that, of course, is the point; "Salome" should inspire the viewer to look within and examine what he or she has in common with these strange, driven people.

The Washington Opera's production facilitates this by stressing its psychological dimension, making the action stylized and giving it a surreal setting. Embedded in the wall of Herod's palace, just barely visible from the audience, is a mirror -- a distorting one of the kind found in amusement parks -- clearly symbolizing the distorted but ultimately recognizable portrait of the human soul that is found in this opera.

"Salome" is, as its title hints, very nearly a one-woman show, and Ewing handles this demanding, complex assignment with an impressive, focused intensity and elaborate attention to small details. Even during the long stretch when she is sitting silent and motionless at stage left, she dominates the performance. Michael Devlin catches with precision the fanatical drive of Jokanaan. Ragnar Ulfung's well-sung Herod is a man trying to be reasonable and ultimately disintegrating under the strain; Joyce Castle is a vividly shrewish Herodias; and Stephen O'Mara a sympathetic Narraboth.

The numerous minor roles are vividly filled by some excellent local singers, and Schwarz gets outstanding work from the orchestra. At the beginning of the evening, Ewing's voice was often covered by the orchestral sound, but this was eliminated as she warmed up. Devlin's voice also had trouble being heard when he was singing from the depths of his dungeon, and something should be done to secure a better balance in later performances.