One is not likely to add any original critical response to the discussion of the legend that is Joni Mitchell. Both as a songwriter and a vocalist, her work has assured the indelible printing of her name on the list of musical giants of the last dozen years.

What one can do is assure Ms. Mitchell's fans that, as her breathtaking concert Wednesday night at the Greek Theatre proved, her developing interest in the jazz idiom has not caused her to lose sight of the qualities that endeared her to a generation of folk-rockers. She has successfully created a set that incorporates the best elements of her jazz experimentations while retaining enough of her old flavor to please all but the most reactionary of her fans.

This was a concert of exceptional balance and pacing, taking the viewers through the entire gamut of emotions but never allowing them to waver in their attentiveness. Given Ms. Mitchell's preoccupation with jazz in recent years, particularly on the current album tribute to jazz legend Chalie [sic] Mingus, the last song she might be expected to sing would be "Big Yellow Taxi," the hit single which so spiritedly expressed her concerns about making a parking lot out of the People's Park in Berkeley. This was the most commercial song she has ever recorded, and commerciality certainly has not been her concern of late. Yet, Ms. Mitchell did, in fact, open with "Taxi" and appropriately closed out the night with a solo rendition of her anthem for that aforementioned generation, "Woodstock."

In between those two songs, we saw a sophisticated Joni Mitchell, much unlike the shy, hippie wanderer who last played the Greek while opening for Crosby, Stills, Nash and Young in 1970; she was more confident, even, than the emerging woman who recorded her live "Mile of Aisles" at the Universal Amphitheater in 1974. On this tour, without trying very hard, Ms. Mitchell looks like she stepped out of the pages of Vogue directly onto the stage. Knickers, polka-dot silk blouse and expensive, open-toe pumps are not, after all, standard rock 'n' roll apparel.

Ms. Mitchell now fronts a jazz band composed of all-star musicians who have in a short while achieved an ensemble sound to be envied by bands that have performed together for 10 years. Michael Brecker is on horns, Jaco Pastorius is the bassist, Pat Metheny is the lead guitarist, Don Alias mans the drums and congas and Lyle Mays is on keyboards. Each player, with the exception of Mays, received appreciable solo time, primarily for the long introductions to the dense, multi-layered instrumentation which backed Ms. Mitchell's poetic vocals. Those solos were unstructured enough to allow Pastorius to stop in mid-flight and walk over to turn up his amp before finishing with some Jimi Hendrix licks.

Ms. Mitchell feels she is a more skillful jazz than rock vocalist. Her instrument, she says, is better at moderate volumes, where she can best utilize the dynamics of range, phrasing and slurring, as opposed to the high volume and simple rhythms of rock. With the remaining material, Ms. Mitchell proved herself right. She can fit any lyric into any melody. The absolutely superb "Amelia," which she dedicated to Gore Vidal - "because he stole on of my metaphors" - might have stirred the long-lost aviatrix Erhardt [sic], wherever she is. If Ms. Mitchell's voice did not, Metheny's eerie, ghost-like guitar most certainly did.

Alias' sensitive, yet powerful touch with the congas opened "Dreamland," Ms. Mitchell's Afro-rhythm experiment, on which the rest of the band added instrumental and vocal percussion. "Furry Sings the Blues," the poignant tribute to blues singer Furry Lewis, then was followed by "God Must Be a Bogey Man," the song she wrote after reading the first part of Mingus' autobiography. The audience provided choral accompaniment at Ms. Mitchell's request.

Nothing represented the dual nature of the concert so much as the segue from the very difficult Mingus tune to "Raised on Robbery," which proved that this band can rock when it wants.

The opening act, the five-part a capella harmony group, "The Persuasion," then was brought back to help Ms. Mitchell with "Wrong and Right," a sensitive statement against the idiocy of racism, and a version of Frankie Lymon's "Why Do Fools Fall in Love."

If the rapturous response at the Greek Wednesday night was any indication, Joni Mitchell is not losing any fans while she explores other musical idioms - she is taking them right along with her.