Four ballerinas, long hair floating to their waists, began their first rehearsal for Jerome Robbins' "Afternoon of a Faun" in a Pacific Northwest Ballet studio last week. Stager Bart Cook, a former New York City Ballet dancer who was Robbins' ballet master for many years, started them off not with steps and positions but with a mood.

The ballet takes place in a rehearsal studio, on a hot day. "You're wearing new shoes," he told the women, "and you've just washed your hair." A young man is stretched out on the studio floor, sleeping like a cat in a sunbeam. The music shimmers, like a quiet lake in midsummer, and you can feel the heat hanging in the air.

A 10-minute ballet for two dancers (four duos are rehearsing it, so as to have multiple casts available), "Afternoon of a Faun" was choreographed by Robbins in 1953. The music is by Claude Debussy (it was previously, and famously, turned into a dance by Vaslav Nijinsky in 1912); the sun-drenched set and lighting created by Jean Rosenthal. "Faun" returns to PNB for the first time in nearly 30 years as part of the repertory evening "Love Stories," beginning Friday.

Cook, who joined NYCB in 1971, remembered what he'd been told about the origins of Robbins' "Faun." "The old School of American Ballet was on Broadway and 83rd. You had to walk downstairs into the studios, and there were bays of windows; the sun would stream in in the afternoon. The story goes that [Robbins] walked by one of the studios and saw Eddie Villella sleeping in the sun."

Villella would go on to be one of NYCB's legendary male dancers. But that day, he was just a teenage student, taking a break during a long day, and Robbins was struck by the image of youth, by the idea of the faun encountering a nymph. He imagined a young ballerina entering the studio and finding the sleeping boy, resulting in a pas de deux both erotic and innocent. The dance is brief, ending with the girl unable to accept the boy's kiss, but "it feels monumental," said Cook; the music and movement combine to cast a hypnotic, gentle spell.

Though Robbins was notoriously insecure about his works, Cook said that "Faun" was one close to the choreographer's heart. It was one of Robbins' early ballets, coming just a few years after he joined NYCB as associate artistic director under George Balanchine. "He knew it inside out, every gesture," said Cook. "I was lucky to be allowed to be in the room, to see him [stage the ballet] with quite a few people." For a long time, Cook said, "Afternoon of a Faun" was performed by the same handful of NYCB dancers, even as they grew older, as Robbins trusted that they understood the work. "[The dancers] used to joke and call it 'Afternoon of a Buck,' Cook said.

As he shapes "Faun" at PNB, Cook will focus on re-creating exactly Robbins' vision, down to the smallest gesture: the adjustment of a shoe ribbon; the tilt of a wrist. In rehearsal, he reminds one of the women that while the role has a certain glamour, it needs to "ride on the innocence. You can't go the other way around — it says a whole different thing. It still speaks, but that's not what [Robbins] wanted." The ballet, he says, is quick and easy to teach — it's brief, and the movement isn't complicated — but it's the details that make it so haunting, and much time in rehearsal will be spent pulling the dancers back, making sure they don't do too much. "There's not one extraneous movement; it's tailored so beautifully."

"Afternoon of a Faun" is part of a gradual build-up of Robbins repertory at PNB: Artistic director Peter Boal (who also worked with Robbins at NYCB) has added many of the choreographer's dances to PNB's roster since arriving here in 2005: "In the Night," "Circus Polka," "Fancy Free," "The Concert," "West Side Story Suite," and the neoclassical masterpiece "Dances at a Gathering." Each shows the trademark Robbins merger of ballet with drama, as befits a man who divided his career between NYCB and the Broadway stage.

The drama of "Afternoon of a Faun" is quiet but emphatic; affecting its viewer subtly yet unforgettably. "People can watch it and not know what's happened to them," said Cook, who's been studying "Faun" and its nuances as a stager for more than 40 years. "I think that's a sign of something that's truly meaningful, that it can affect you without you being able to define it."

The "Love Stories" evening will also include the PNB premiere of George Balanchine's 1972 ballet "Divertimento from 'Le Baiser de la Fée,' " set to music by Igor Stravinsky, as well as pas de deux excerpts from "Roméo et Juliette" (set to Sergei Prokofiev's music; choreographed by Jean-Christophe Maillot); "Swan Lake" (Peter Ilyich Tchaikovsky/Kent Stowell); and "The Sleeping Beauty" (Tchaikovsky/Ronald Hynd).

Moira Macdonald: 206-464-2725 or mmacdonald@seattletimes.com