"Sexual arousal," says soprano Maria Ewing without any hesitation. She is talking about "Salome," a role she is singing these days at the Kennedy Center. In "Salome," she says, "arousal comes in many forms, but it's all the same. Everyone in the opera is obsessed, erotic and crazy." Nobody more so than the Jewish princess Ewing portrays with an almost terrifying intensity: a young woman who will accept no denial or contradiction, who knows her erotic power, uses it to get her way and causes the deaths of two men: one because he cannot say no to her and one because he refuses to say yes.

In private conversation, Ewing, tall and slender, is elegant and quietly self-contained until she begins talking about opera and acting; then her voice becomes animated and she has a deep, earthy laugh -- the laugh of a woman who says she is very shy but does not mind dancing nude before 2,000 people if it makes artistic sense. Her exotic good looks (inherited from a Dutch mother and a Sioux father) are even more impressive up close and without makeup than they are when she is onstage. She is 40 years old, looks less than 30, and is totally convincing when she impersonates a spoiled, sensual teenager who dances an elaborate, Oriental striptease to gain power, uses that power to kill the man who rejected her and then scolds and fondles his severed head.

Next year, she will sing for the first time the role of Madame Butterfly, who commits suicide when her lover rejects her. In her own way, but a very different way, Butterfly is an untamed woman deeply concerned with Eros, or she will be when Ewing brings her onstage. "People think the Japanese are cool and unemotional," she says, "but really they are not: They are restrained, self-contained, but in their art and their lives, when the emotion breaks out, it can be explosive."

She is now on the outer edges of the process of looking inside Maria Ewing to find Madame Butterfly. "You have to be a part of the character," she says. "I'm really not one to sort of sit down and analyze -- outside of myself, so to speak. I understand a role as I go along. ... As I learn it musically, sitting at the piano, it happens at once. I learn the notes and also what it means dramatically, and there's no way of separating the elements."

Has she looked inside Maria Ewing to find a person who would demand a man's head on a silver platter? She hesitates momentarily then breaks into that rich laugh. "Yes," she says. Does the answer disturb her? Of course; it's supposed to. " 'Salome' is such a disturbing and shocking and fascinating and wonderful and horrible piece," she says. "On the one hand it is such a bizarre world, and such horrific things happen, but in my view the basic psychological element of the piece is known to us all. We may not want to accept that, and we don't necessarily understand it, because it's so complex, but it's in all of us. It's not a piece where you say, 'Oh, I love this'; it's 'I'm -- I'm upset.' My friends have been coming to see it, and it's disturbed them very much. In a wonderful and a very exciting way."

Ewing became a singer almost by accident. Growing up in a music-loving family, the youngest of four daughters (her father was an engineer, her mother a good singer but not a professional), she studied piano and sang occasional duets with her sister Frances. One day her mother told Maria, "You have a voice," and she recalls wondering, "Doesn't she like my piano-playing?" But she joined her school choir, whose director got her a voice teacher, Margery Gordon, and made her enter competitions, which she began to win. By age 19, Ewing was singing the role of Rosina in "The Barber of Seville" with the Michigan Opera.

Now, she is one of the world's most famous singers, though she says she finds fame "meaningless ... a bother, really, and a problem for the well-being of music. You have no control over it; stardom is in the eyes of the beholder. There are too many young singers now who are interested only in fame, not in doing a job and doing it right. There is an emptiness in that kind of ambition, like the emptiness you find in most American television and in a lot of American acting."

Not that she has any superior feelings about popular arts, particularly popular music when it is done with skill and care. "I like to hear good jazz when I am not working; I go to more jazz concerts than classical music programs. And I think that most of the world's opera singers could learn a lot from Frank Sinatra and Judy Garland," she says.

Despite her operatic credentials -- she sang "Tosca" last year in Los Angeles and has sung "Carmen" outdoors, for audiences of 15,000, in London -- Ewing says that "it's not completely accurate to call me an opera singer; it's not the only thing I do." This year, besides "Salome" and "Carmen," Ewing is doing a lot of work in concerts and recitals: George Gershwin and Cole Porter as well as but not on the same programs as Strauss, Schubert and Debussy.

The first role in which she found her deepest self reflected was that of the composer in "Ariadne auf Naxos," a character clearly modeled on Mozart -- young, impetuous, dedicated to music as a kind of heavenly ideal. She read the part, words and music, when she was 18, dreamed of singing it onstage and discussed it with her mentor, James Levine (who was then the assistant conductor of the Cleveland Orchestra, later to become artistic director of the Metropolitan Opera).

She made that dream come true, but not for years -- not until 1980 when she was 30 years old and sang it at the Glyndebourne Festival. "Other parts that move me in a special way are more down to earth," she says. "I love Tosca for her devotion to her art and her lover, for the way she loves. And I think it will be fascinating next year to play a part like Cio-Cio-San {Madame Butterfly}, a strong woman but utterly self-sacrificing."

The role for "Salome," playing at the Opera House through Nov. 23, is "the most physically demanding" role she has ever sung, although it is a short opera. "Everything is so condensed in those two hours," she says. "I cannot imagine anything more intense." The fact that she has a long, elaborate dance sequence doesn't make it harder, though. It makes it easier: "I find it very exhilarating. It helps the last scene {the long, insanely erotic monologue with the head of John the Baptist}. Just the physical act of it is a very good thing. By the time you finish the dance and go into that last scene, you find that you're prepared for it physically and in the right state of mind psychologically. I can't imagine the dance being danced by another person -- you know, the singer going offstage to rest and a dancer coming on to pretend she is Salome. It has to be the same performer -- the girl -- she has to do all of it because it all works together.

"I've always loved dancing; if I had a second choice, I think I would be a dancer, but I've never studied classical dancing or modern dancing," she says. Before becoming a professional singer, she thought of working in psychology, but being a singer was "not really a matter of choice," she says. "There are certain things that you simply have to do; there is a driving force that takes possession of you and says, 'You will do this.' We're called performers; I don't like that term -- like performing animals in a circus; I'm not doing some kind of trick. There are matters of technique, of course, but the most important part is not something you control."

Nobody told her to end her Dance of the Seven Veils with nudity, though she worked closely with a choreographer developing the dance. Her interpretations come from inside, not from the suggestions of a director -- even Peter Hall, the father of her 8-year-old daughter, Rebecca, who tailored this production of "Salome" for her and from whom she had a much-publicized divorce. "In the very early days, when a director would say, 'Do this, or do that,' I would go outside of myself and try to follow directions," she says. "It wouldn't work; it wasn't me. And you have to draw the line. I am expressing myself up there, and I do love it. I go through the experience of Salome each time; it's never routine, always different. If it were not, something would be dead and I couldn't do it anymore. I go to the edge of a precipice each and every time; it's a very dangerous precipice, and nothing to take for granted."