Veronika Part was already a star at the Kirov Ballet when she left Russia to join American Ballet Theatre in 2002. But over the last three years, Ms. Part, now 27, has become a greater artist than she was in Russia. Though she still has her critics, her performances over the last week at City Center have shown her work to be an exemplary lesson in the art of the ballerina.

Her transition has not been easy. Ms. Part’s debut during the fall 2002 City Center season – she danced the adagio in Balanchine’s “Symphony in C” – was one of the most tense performances I’ve ever sat through. I could feel the hostility of her fellow dancers, and of pockets of the audience wary of this potentially usurping outsider. Nor was Ms. Part in her best form that night: She was visibly nervous and rather wobbly, and she had gained weight since the Kirov’s New York season three months earlier.

She has since become streamlined – tall, beautifully proportioned, curvaceous – but she will never be bonethin. That is one of her glories: It gives her a unique opulence that the amplitude and sensuality of her movement enhance.

Last spring, during ABT’s two-month season at the Metropolitan Opera, Ms. Part came into her own as a presence in American ballet. She danced an enormous repertory, from soloist slots to ballerina leads, in every conceivable style. She again danced the dual role of Odette/Odile in “Swan Lake,” which she had first performed with ABT in 2004. When I had first seen her dance Odette/Odile, in London with the Kirov in 2000, her performance had demonstrated a beautiful plasticity. But while the shapes she made were expressive, the emotion behind them was superficial. Now her “Swan Lake” is among the most vulnerable and impassioned to be seen anywhere. It is all but rocked by an emotional urgency that was not there before.

This season, I was very curious to see her return to the role of Terpsichore in Balanchine’s “Apollo.” I had last seen her do it during the Kirov’s 1999 New York season, and it was one of her rare performances I didn’t like. In general, I do not like the way Terpsichore becomes a coy minx when the Kirov performs this role.

On Thursday night, Ms. Part’s performance embodied a different gravitas. When she first appeared on stage, she was remote, possessed by her mission to ensure that Apollo assumed his divinity. She understood that Terpsichore, muse of dance, is an infinitely faceted embodiment of the eternal feminine. While she can be consort, mother, inspiration to Apollo, when Terpsichore dances the adagio with him they are not wooing each other. Though she still has room to develop in this role, her return to “Apollo” was triumphant.

The following night, Ms. Part moved from neo-classicism to neo-romanticism, making her debut in “Les Sylphides,” which she repeated Saturday. At both performances, the scale and evocative power of Ms. Part’s movement were frequently magnificent. All of her joints seemed to be completely rotated and flexible, and there was never any intimation of constriction; this made her suited to embody an apocryphal creature like a sylphide. Her body bent organically so that she actually suggested a sighing willow or a swaying bough. When her arms brushed down to the ground, they went all the way down in an exhalation of bestowing. Dancing the Prelude solo, she seemed drawn by a magnetic attraction, an invisible partner made tangible by her limitless power of suggestion. She was never static, even when still.

Ms. Part has accumulated a vociferous following, but she is also rather controversial (when you come down to it, virtually every performer is: the more distinctive, the more vigorously debated.) I confess that I find specious the claims about her alleged technical weakness. She is primarily an adagio ballerina, not an allegro technician, and adagio technique requires a unique strength and control that is often closed to allegro technicians. Very few dancers, for example, can extend their leg in a slow, high, sustained developpe with the ease and security of Ms. Part.

Ms. Part cannot pirouette until the cows come home, but she pirouettes with perfect aplomb. She can perform batterie, and she has a huge jump. At the Met last spring, she danced Balanchine’s “Ballet Imperial,” which is almost always given to an allegro virtuoso. Her name was listed for the ballet in casting published months before the season. I thought she would never actually dance it, that the company was making her rehearse simply as a vehicle to improve her speed. But dance it she did – twice. She did it her way, which included slowing down the orchestral tempo. Yet she performed it honestly. I was impressed by how much of the role was within her reach.

Ms.Part again demonstrated her versatility this season, when she danced a role created for her by Peter Quanz in “Kaleidescope.” Mr Quanz’s new ballet imaginatively deployed the expansive extremes of her range: One moment she slinked low to the ground in a deep plie, the next she towered on pointe in the most regal arabesque imaginable. Quick, scissory jumps in the closing allegro movement demonstrated the fascinating way in which she imparted a velvety texture to steps that are traditionally crystalline. Mr. Quanz had sensitively tooled Part’s delightful unpredictability, her gift for showing the unexpected, for revealing physical nuances that make ballet articulate.

Ms. Part will perform in “Apollo” on November 5 at City Center (131 W. 55th Street, between Sixth and Seventh Avenues, 212-581-1212).