'A Tribute to Joni Mitchell,' Nonesuch

Joni Mitchell doesn't suffer fools gladly, and she has even less use for sycophants. So those brave souls who decided to accept "Mission Nearly Impossible" - to cover Mitchell's work in a manner worthy of her - had their work cut out for them.

The Mitchell tribute disk has been in the works for years, hemming and hawing its way through an ever-shifting cast of participants. (Among those eventually kicked to the curb: Janet Jackson, who, believe it or not, cut a version of 1988's "The Beat of Black Wings").

Those who made the grade mainly followed Mitchell's mandate for how to approach her songs: Instead of Xeroxing the original, warp the song your own way.

Some did so to the point of the perverse. Sufjan Stevens sends "Free Man in Paris" careening through four tempo changes in as many minutes, shuttling between a fruity horn chorale, a strident march, and a pretty new melody. There's some beauty in his take, but too much jerking back and forth to sustain it.

Sarah McLachlan's version of "Blue" suffers from the opposite problem: She found nothing in it of her own. While James Taylor turned the melody of Joni's holiday-from-hell classic "River" upside down, his vocals have too much poise to capture the song's despondent undertow.

A far more successful reinvention arrives in Bjork's "The Boho Dance." She gives the gorgeous melody a dreamy new sheen. It's also interesting to hear such an arch artiste embrace a song that expresses pure bourgeois desire.

Caetano Veloso uses a slinky samba to inject a new sexiness into "Dreamland," and Cassandra Wilson lends an erotic spookiness to "For the Roses." Elvis Costello raises the already complex "Edith and the Kingpin" to erudite new heights with his orchestral arrangement, while k.d. lang relieves an otherwise routine reading of "Help Me" by awarding its hook a gymnastic spring.

But the greatest contribution is the cast's emphasis on Mitchell's musical side over that element which normally makes all bow before her: her burning words. Emmylou Harris does a public service by illuminating the tune in the underappreciated "Magdalene Laundries." And Brad Mehldau does away with the lyric of "Don't Interrupt the Sorrow" entirely, making it a roiling jazz instrumental.

That's the best thing a cover version can offer - a way for longtime listeners to hear new things in songs they thought they knew by heart.