If you think of chords as clouds, a couple things might pop into your head. At least they do in mine. There's the opening shot of "The Simpsons," with its heavenly symphonic swell and aerial view of Springfield seen through parting clouds. Then there's Joni Mitchell's most famous song, "Both Sides Now." I think it's safe to say this song was how many people first encountered this artist, a figure so towering it's not hard to imagine her gazing down from above our puffy friends.

In a career that went from coffee house confessionals to jazz experiments, certain things have been consistent throughout. Her obsession with movement - skating, driving and flying. Then there are the landscapes she moves through and above, a vast open sky, the one she must have fallen from. Few would disagree that as a young woman she appeared to have walked out of a renaissance painting, leaving wings and halo behind. Her voice, almost always described as angelic, adds to the effect.

People compare her to Bob Dylan, I suppose because they both were strumming acoustics and singing their own songs. It's hard to think of any other similarities, aside from ambition and stubbornness. But Dylan is of the earth and the ethereal Ms Mitchell has let it be known more than a few times she views him as a charlatan. We'll let the gods battle that one out, but I have to admit it's fun to hear her bust his chops. The high degree of polish in her work is another way she counters Dylan and his fast loose style. I doubt that was intentional, it's just what she does, and much of it begins with her guitar. Unlike a lot of artists, Joni prefers to stay uncomfortable on her instrument, using open tunings to reshuffle the deck harmonically. This keeps things interesting. You put your fingers where they usually go and you get chords you've never heard before. Surprise! Doing that allows her to avoid the stale and the stock as she works her way home from some strange terrain she's created. The line she follows out of these puzzles is always melodic, reliably great in her case. A perfect example is found in the song "Amelia", from her album "Hejira." Like the famous aviator she sings about, Mitchell is at home wandering the skies. They're not always friendly and, unlike her subject, she doesn't have the luxury of a navigator.

I was driving across the burning desert
When I spotted six jet planes
Leaving six white vapor trails across the bleak terrain
It was the hexagram of the heavens
it was the strings of my guitar
Amelia, it was just a false alarm

The drone of flying engines
Is a song so wild and blue
It scrambles time and seasons if it gets through to you
Then your life becomes a travelogue
Of picture-post-card-charms
Amelia, it was just a false alarm

People will tell you where they've gone
They'll tell you where to go
But till you get there yourself you never really know
Where some have found their paradise
Others just come to harm
Oh Amelia, it was just a false alarm

I wish that he was here tonight
It's so hard to obey
His sad request of me to kindly stay away
So this is how I hide the hurt
As the road leads cursed and charmed
I tell Amelia, it was just a false alarm

A ghost of aviation
She was swallowed by the sky
Or by the sea, like me she had a dream to fly
Like Icarus ascending
On beautiful foolish arms
Amelia, it was just a false alarm

Maybe I've never really loved
I guess that is the truth
I've spent my whole life in clouds at icy altitude
And looking down on everything
I crashed into his arms
Amelia, it was just a false alarm

I pulled into the Cactus Tree Motel
To shower off the dust
And I slept on the strange pillows of my wanderlust
I dreamed of 747's
Over geometric farms
Dreams, Amelia, dreams and false alarms

The line, "Amelia, it was just a false alarm" stays in my head. It doesn't mean anything in particular, it's beautiful because it's beautiful. The chords wander about in a songful cloud. They don't don't wind up in the same place, they have to reset for each verse, moving up a whole step before she can sing again. The lack of bridge should be a problem, if you subscribe to the orthodox view of songwriting. She obviously doesn't and it works just fine. The seven verses create a kind of delirium, coming at you in waves, crashing and building up again. Rootless, restless and searching, they could have told the story by themselves: There is no place to land.

It's no coincidence Joni Mitchell should sing about a woman adrift in a man's world. She had her own Lindberg in Dylan and may have sensed his shadow needlessly dimming her reputation. In so many of her songs, women struggle as men let them down. "The Hissing Of Summer Lawns" paints a picture of suburban boredom. "Free Man In Paris," which she sings from a man's point of view, is a wicked parody of power and money in the ultimate man's game, the music business.

I chose a live performance of this song for a reason. The record, of course, is perfection, featuring the tasty guitar swells of jazz great Larry Carlton and vibes from Victor Feldman. But hearing it the way it was created, with voice and guitar, removes any doubt it was studio trickery or the skill of other musicians that made it so memorable. I had to go get my guitar to see what she was doing. It seemed easy, but wasn't. I sat for a long time trying to figure out these tricky changes and after much trouble, I got them. But the thing will always elude me, the unsolvable puzzle I ponder everyday when it comes to artists of her stature, is how something like this, which didn't exist for an eternity and now seems absolutely necessary, came to be.