THE off-kilter melodies of singer-songwriter Joni Mitchell have spanned folk, pop-rock and jazz in a three decade career which has seen more than 20 albums.

Her memorable tunes like Both Sides Now, Big Yellow Taxi and A Case of You have been sung by dozens of stars from Sinatra to Madonna.

Born Roberta Joan Anderson in Alberta, Canada in 1943 she now spends more time painting than making music.

But in the late 1960s and early '70s music was her life.

And she threw herself into it with gay abandon.

A blonde-haired troubador and darling of the hippy US folk scene, musician David Crosby said his first meeting with her was like being hit by a hand grenade.

He said, "Her voice, those words, she nailed me to the wall with two-inch spikes".

Joni Mitchell invented the confessional singer songwriter movement and her enthusiastic and fast moving love life gave her plenty of material.

A 36-hour courtship then equally swift marriage to folk singer Chuck Mitchell resulted in a child she gave up for adoption.

She held late-night poker and booze parties with the likes of Buffy Sainte-Marie, Gordon Lightfoot and Neil Young.

She had passionate affairs with Crosby, James Taylor, Graham Nash, John Guerin, Jaco Pastorius and bassist Larry Klein who she married and divorced.

In the late '60s she left smog- bound LA to head for the paradise of Hawaii.

But found many hotels had taken swathes of land to cater for tourists' cars.

Hence her Big Yellow Taxi lyrics, "Don't it always seem to go, That you don't know what you got till it's gone, they paved paradise and put up a parking lot".

Like many of her songs the words are intensely personal but can somehow attach to a myriad other situations and places.

Other classics such as Free Man in Paris, Both Sides Now and Help Me are all about her life.

On her seminal Joni album, was based on the Cretan seafront village of Matala, favoured by folk stars such as Bob Dylan who hung out in the sun soaked Mermaid Cafe by day and slept in caves at night.

Blue was followed by For the Roses (1972) and Court and Spark (1974) then in 1975 the critics started to turn when she produced the heavily jazz influenced The Hissing of Summer Lawns in 1975. Her foray into jazz received critical acclaim in many quarters while slammed by folk purists.

Whatever the merits of the jazz move it seemed that Joni Mitchell had reached her peak, at least for the popular market. Ironically, her appearances co-incided with the collapse of the hippy era.

She missed Woodstock, the 1969 mega-festival at Max Yasgur's farm due to other commitments but her song about the hippy gathering, Woodstock, seemed to sum up an ear of peace, hope, folk and pot.

Just a year later she attended the Isle of Wight Festival. This time things had changed.

There was a dark mood of paranoia, greed and anger hanging over the festival with many of the crowd feeling they were being ripped off and jumping a fence to avoid expensive entry fees.

Joni's performance was interrupted by a spaced out, bearded Manson lookalike called Yogi Joe who claimed, "I am the head of the official committee to paint the fence invisible".

It signalled the end of something beautiful even though Joni herself had plenty of songs still left in her.

And in the words of David Crosby, "She's the best singer- songwriter there is, man..."