From the moment Joni Mitchell's career began -- with coffee-house bookings, serendipitous encounters with established stars, and a recording contract that gave her full creative control over her music -- the woman from the Canadian wheat fields has eluded industry cliches. When her peers were focused on feminism, Mitchell was plumbing the depths of her own human condition. When arena rock was king, she turned to jazz. When all others hailed Bob Dylan as a musical messiah, Mitchell saw a fraud burdened with halitosis. Unafraid to