“The moment I began to write, my music was not folk music.” Performing solo with her acoustic guitar and long, straight, blond hair, the woman born Roberta Joan Anderson in Fort MacLeod, Alberta, Canada, on November 7, 1943, may have looked the part, but in truth the only category that fits the groundbreaking singer-songwriter better known as Joni Mitchell is Duke Ellington’s famous superlative: “beyond category.”

Even as a child taking piano lessons, Joni Mitchell showed more interest in composing her own melodies than in playing the pieces her teacher assigned her. “My teacher rapped my knuckles with a ruler and said, ‘Why would you want to compose when you could have the greats under your fingers?'” she recalled in an interview some 40 years later. When the folk-music revival of the late 1950s and early 1960s came to Saskatoon—the college town in which she spent most of her childhood—Mitchell resolved to learn the guitar in order to become a competent accompanist at sing-alongs. When her mother refused to chip in, citing Joni’s earlier abandonment of the piano, the woman Rolling Stone would later name the greatest female guitarist of all time saved up and purchased a baritone ukulele.  

A bout with polio as a child had left Mitchell unable to form the chords with her left hand that her ear wanted to hear, so early on she began experimenting with non-standard guitar tunings that would later become part of her signature sound. It was not as performer, however, but as a songwriter that Mitchell would initially make her name. Even many of her biggest fans first heard Joni Mitchell’s music as interpreted by Judy Collins, who made a hit out of “Both Sides Now” (1967) fully two years before Mitchell released her own recording of that song herself. In later years, Crosby, Stills and Nash would score a bigger hit with the Mitchell-penned “Woodstock” than Mitchell herself would, as would hard-rockers Nazareth with their 1973 cover version of “This Flight Tonight,” from Mitchell’s landmark album, Blue

Blue (1971) marked the beginning of Mitchell’s period of greatest popularity, and her commercial success peaked three years later with 1974’s Court and Spark. But even though she would never sell as many records in the subsequent decades as she did in the early 1970s, her creativity only increased as she experimented and collaborated with jazz greats like Charles Mingus and Herbie Hancock. In a judgment that history has already recorded as very sound, David Geffen of Geffen Records, Mitchell’s label from 1982 to 1993, said in 1994, “Even though we lost money on every one of her records, we always treated Joni as one of the most important artists in the world.”