Who but Joni Mitchell would have the nerve to record a tribute album to herself?

On the gutsy singer's latest release, she reconsiders 22 songs from her own catalogue, with the help of the 70-piece London Symphony Orchestra.

Given the breadth of Mitchell's talent, she deserves the self-salute. As a lyricist, she should be enshrined in a triptych with Bob Dylan and Leonard Cohen as the greatest wordsmiths of the last half century. As a musician, Mitchell long ago became inimitable, boasting a style so daunting and quirky it's nearly impossible for other artists to cover her stuff.

In fact, there is already a multiartist tribute album to Mitchell, cut several years ago, which is languishing in the vaults. God knows what it sounds like. But in the meantime, we have the creator herself to give these amazing songs a second life.

The impetus to do so grows out of Mitchell's last project, 2000's "Both Sides Now" - an album in which she covered American standards with the London Symphony Orchestra. She had the temerity to place two of her own compositions in that vaunted company  the title cut and "A Case of You." As it turned out, both those songs stood comfortably shoulder to shoulder with those by writers like Irving Berlin and George Gershwin.

Still, covering the Mitchell classics on the new album invites some itchy comparisons.

Even the liner notes to the CD warn longtime fans to warm up to these versions slowly. To say the least, Mitchell's voice has changed over the years. This lifelong heavy smoker has moved from a girlishly flighty soprano (until 1973) to a grandly fluid alto (from the mid-'70s to the late '80s), to a singer hampered by some serious technical limitations (in the '90s).

While some singers gain character from damage, in Mitchell's case the years have made her tone increasingly shallow and coarse. Her range has narrowed to the point where it affects her ability to express herself.

For this reason, it's easier to accept the covers of her more recent songs, like 1994's "The Sire of Sorrows" or "Borderline," where there's less degeneration from the versions we already know. It's more difficult to hear Mitchell gingerly work her way through once-soaring '70s classics like "The Last Time I Saw Richard" or "Amelia."

What she's doing here sometimes seems less like singing than orating: Think Rex Harrison in "My Fair Lady." Essentially, she's narrating these songs. But the approach gives the pieces a strange and intriguing new perspective.

In older songs, like "Trouble Child" or "For the Roses," Mitchell isn't singing as the scared and volatile character described in the songs, but rather as the observant author of them. And that puts a fresh focus on every burning word.

If Mitchell's vocals can seem detached from the immediacy of the experience, she connects to a newly considered point of view. Placed amid the grandeur of the orchestral arrangements, Mitchell sounds as if she were looking back at her earthly experiences from the afterlife, delighting in the perceptions and errors of her past with a serene wisdom.

In the end "Travelogue" seems almost like a supernatural piece of theater - unlike anything else out there, and quite apart from anything the artist has done before. From Joni Mitchell, should we expect anything less?