ON ONE LEVEL Clouds seems fairly unexceptional, another instance of the age-old tryst between singer and acoustic guitar.

But in truth it's phenomenal, early evidence of the eloquence and idiosyncrasy which distinguished Joni's songwriting and musicianship. Dissatisfied with David Crosby's foggy production on Song To A Seagull, Reprise initially drafted Paul A. Rothchild (Love, The Doors) to oversee Clouds. But when Rothchild gaffer- taped Joni's feet to the floor after she'd moved them while singing Tin Angel it went way beyond mansplaining. Pioneering a template for female voyagers of independent mind (hello, Kate Bush), Mitchell self-produced the remaining tracks, working with engineer Henry Lewy while Rothchild holidayed. "A producer is a babysitter," she later said.

At 25, Joni brought questioning, unguarded emotional intelligence to Clouds. A visionary reflection on the vicissitudes of friendships, and part-inspired by cloud-gazing from an airplane, Both Sides Now seems precociously wise - though by the time it appeared on Clouds it had already been a hit for Judy Collins. The insight of someone far older than her actual years continued on The Gallery, wherein our former Alberta College Of Art student sings from the perspective of a painter's ageing muse: "I gave you all my pretty years/ Then we began to weather/And I was left to winter here/ While you went west for pleasure."

Clouds is emphatically not someone strumming D. Nine of its 10 songs use ingenious alternative tunings to find inspiring new chord-voicings, most strikingly so on Songs To Aging Children Come, wherein the low E string of Mitchell's guitar is tuned down to a droning B, and her haunting, chromatic vocal melody fights its own war against cliche. The only other musician credited on Clouds is Stephen Stills, but his guitar and bass contributions are minimal. There's only one captain here.

Some critics characterise the bright, breezy Chelsea Morning as unsubstantial juvenilia, but Roses Blue and The Fiddle And The Drum have real gravitas, and move beyond Chelsea Morning's pretty, poetic imagery. The former, built on a tricky, stop-start finger-picking pattern, describes Rose, a seemingly disturbed woman lost to "mysterious devotions... tarot cards and potions", while the latter, sung a cappella despite some challenging movements of interval, is partly a denouncement of US involvement in the Vietnam War.

Blue tends to steal Clouds' thunder, but Clouds was Mitchell's first great folk LP, a spare, searching album about self-discovery and personal authenticity. The self-portrait she painted for the record's cover says 'this is me' - and there was still plenty of Both Sides Now in Mitchell when she re-made the song for her 2000 LP of the same name. Her voice was deeper, certainly, something lost and plenty gained. The new version was cloud-like: gauzy, in-flux, quietly majestic.