Evita isn't the only current musical smash that owes a debt to Juan Perón. Pianist Martha Argerich was 12 when she impressed the late Argentine dictator with her "touch of star quality." He immediately arranged to have her parents assigned to the Argentine embassy in Vienna (where her father served as an economic attaché and her mother as an administrative assistant) so that Martha could advance her musical studies.

Now, at 38, Argerich is widely touted as the best woman pianist in the world (although many would give that distinction to Spain's Alicia de Larrocha). In a time when so many of her peers are indistinguishable, Argerich is a throwback to titans like Rachmaninoff and Rubinstein, with her dazzling ability to charge notes with raw passion. She is equally electric and idiosyncratic offstage. "Martha has a towering personality," says one European friend. "She is quixotic and questing. It must be very difficult to live with her."

Argerich appears frequently in Europe but limits her U.S. concerts to 10 a year (at $10,000 each), preferring to play within commuting distance of Geneva, where her three children live. She is prone to sudden cancellations, once calling in sick three days before a performance with Leonard Bernstein and the New York Philharmonic. "There was hell to pay," recalls her North American manager, Herbert Barrett. "But they invited her back the following year. She can get away with anything because she is that good."

"Martha," says André Previn, a pianist himself who conducted her recently in New York, "has one of the most astounding techniques that I have ever heard—and that includes Vladimir Horowitz. She has a total grasp of what she's playing and she's phenomenally exciting to hear."

Argerich shrugs off the accolades. As recently as last fall she said, "I love to play the piano but I don't want to be a pianist. I have a conflict." She began her studies at 3 and made her first orchestra appearance at 8. "I was extremely shy and didn't enjoy performing," she recalls. "I hated coming out for bows and would rather have just run off the stage." She also disliked practice, "cheating a lot" by reading books like Oliver Twist and Uncle Tom's Cabin hidden in her lap. But at 16, she stunned the music world by winning two awards within three weeks: the Geneva International Jion Competition and the Ferruccio Busoni International Contest in Bolzano, Italy. After these triumphs, a highly successful European tour and an excellent first recording, Argerich gave up the piano at 20. The itinerant life left her feeling "lonely and empty," she says now. "I wasn't enjoying it either as an artist or a person."

She considered becoming a secretary. At 22, she married composer-conductor Robert Chen, but they broke up in 1964 before the birth of her first daughter, Lyda, now 16. Argerich resumed her career and within six months won the coveted Chopin competition in Warsaw. Four years later, in 1969, she married Charles Dutoit, conductor of the Montreal Symphony, and had a daughter, Anne, now 9. The couple was divorced after five years, and Martha took up with an old love, pianist Stephen Bishop, whom she never married but who fathered daughter Stephanie, 5. "We were twice about to marry but never did," says Argerich. "I've not been lucky in these matters. I don't have a very mature attitude about marriage. It never was a great goal or conviction of mine."

She lives in a rented seven-room house in Geneva with her two youngest (for whom she once hired an au pair boy) and several friends. Lyda lives nearby with her father. "Martha has a marvelous sort of primitive love and devotion to her children," says her London manager, Michael Emmerson, "but she is scatterbrained."

Argerich is similarly nonchalant about her appearance and the other details of her life. She dresses like a peasant, wears no makeup ("My hair always hides my face anyway") and keeps her raven mane like a gypsy's. Her diet consists largely of yogurt, mineral water, coffee and champagne. She is a nocturnal creature who practices into the morning or sits till dawn with friends. "I talk and talk and talk," she says. "It's a vice but important to me."

At present Martha is once again romantically adrift—"It's like the Sahara Desert"—but doesn't rule out a third marriage. Artistically, however, she realizes she must get a handle on "my terribly disorganized life" in order to grow. "I hope," she says, "that my best playing is still ahead. Otherwise, I'm dead."