Kenneth MacMillan's Romeo and Juliet sweeps audiences through Prokofiev's score as though the story were not familiar and the ending still in doubt. First staged in 1965 for The Royal Ballet, the production entered ABT's repertoire in 1985, and dancers have vied for the leads ever since.

For many, performing Juliet or Romeo is the ultimate test of dramatic ability. "It's an incredible vehicle," says ABT ballet mistress Georgina Parkinson, who coaches the ballet's main roles. There are scenes that demand consummate artistry and roles that offer leeway for individual interpretation. For ballerinas, there are choices to make from Juliet's first entrance. MacMillan, like Shakespeare, delays his heroine's appearance until the audience has met Romeo and seen the bitter quarrel between the Montagues and the Capulets.

When Juliet finally runs onstage, doll in hand, the ballerina can make her charming, teasing, innocent or self-aware. Her reaction in the same scene to Paris, the suitor her parents present to her, offers a further opportunity. Parkinson, for one, believes Juliet should be shy. "She's flattered, but unsure," says Parkinson, though she notes there are several ways to play it. "Juliet is polite, of course," says principal Paloma Herrera, "but it depends on who is dancing Paris. If he's cold, then I am. If he's warm, I play off that."

For male dancers, Romeo's transformation from swaggering young man to passionate lover offers a rich blend of virtuosity and nuance. "Romeo's like any other guy at the start," says Principal Dancer David Hallberg. "He's roaming around Verona, lost and a little gloomy, shooting the breeze with his friends Mercutio and Benvolio. His life seems incomplete. Once he meets Juliet, he never questions it again."

The breathtaking lifts and leaps in Romeo and Juliet's first pas de deux make technical demands that must disappear in performance. "The choreography's all about that first time," says Parkinson. "You want the dancers to look spontaneous." Herrera likes to rehearse until she feels completely comfortable with her partner. "The audience shouldn't see the steps," she says. "It should look like we're making it up as we go along." Hallberg has a similar view. "You need to get the kinks out. With Romeo, you can't be thinking about your turnout‹you have to embody the character."

Yet one of the ballet's biggest theatrical hurdles involves no technique and little rehearsal. After Romeo flees for his life, and Juliet has been told she must marry Paris, she is left alone on stage. She walks quietly to the bed where she and Romeo have slept, faces the audience and sits. Several minutes go by as she remains absolutely still, and Prokofiev's music swells from the orchestra.

"It's the moment when Juliet is transformed from a young girl to a woman, and it's a challenge for many dancers," says Parkinson. "The music says everything. I don't think a dance step would work. There are many layers‹despondency, then thinking, growing confidence. Macmillan wanted it left to the ballerina." Herrera finds the scene emotionally intense. "It should be powerful, but you don't move‹it's all in your presence," she says. "You either control that stage or you don't."

The ballet's final moments can be among the hardest to perform. When Romeo enters the crypt and finds Juliet seemingly dead, he dances a last desperate pas de deux with her lifeless body, a feat of technical legerdemain that can easily look fake. "Juliet has to give the illusion of being completely limp, but she's not really," says Parkinson. "That's why it's brilliant. The ballerina has to hold herself so she's not a dead weight, and there are times when she helps her partner by pushing off the floor a bit, but the audience can't see it."

Hallberg learned the crypt scene several years ago in front of an audience as part of a demonstration, and remembers fearing it would look silly. "It's different in the context of the ballet, when there's such a buildup to that moment," he says. "Everything has come crashing down on the lovers. Even if you're the worst actor in the world, you can't help feeling devastated for Romeo." He looks forward to the ballet's challenge, but feels anxiety as well. "Whenever you take on a colossal role like this, nerves and doubt kick in," he confesses. "There's a real responsibility to do it justice."

Romeo and Juliet has earned a passionate following among audiences as well as dancers. "It's such a glorious production," says Parkinson. "It's no wonder audiences become emotionally involved." Dancers have a similar reaction. "After I dance Juliet," says Herrera, "I feel fulfilled, but empty too. You have given so much of yourself to the role, and it has given so much to you."