Folk music includes both traditional music and the genre that evolved from it during the 20th century folk revival. The term originated in the 19th century but is often applied to music that is older than that. Certain types of folk music are also called world music.

Traditional folk music has been defined in several ways: as music transmitted by mouth, as music of the lower classes, and as music with unknown composers. It has been contrasted with commercial and classical styles. One meaning often given is that of old songs, with no known composers; another is music that has been transmitted and evolved by a process of oral transmission or performed by custom over a long period of time.

Starting in the mid-20th century a new form of popular folk music evolved from traditional folk music. This process and period is called the (second) folk revival and reached a zenith in the 1960s. This form of music is sometimes called contemporary folk music or folk revival music to distinguish it from earlier folk forms. This type of folk music also includes fusion genres such as folk rock, folk metal, electric folk, and others. While contemporary folk music is a genre generally distinct from traditional folk music, in English it shares the same name, and it often shares the same performers and venues as traditional folk music. Even individual songs may be a blend of the two.

Joni Mitchell, CC (born Roberta Joan Anderson; November 7, 1943) is a Canadian musician, singer songwriter, and painter. Mitchell began singing in small nightclubs in Saskatchewan and Western Canada and then busking in the streets and dives of Toronto. In 1965 she moved to the United States and, touring constantly, began to be recognized when her original songs ("Urge for Going," "Chelsea Morning," "Both Sides, Now," "The Circle Game") were covered by notable folk singers, allowing her to sign with Reprise Records and record her own debut album in 1968. Settling in Southern California, Mitchell and her popular songs like "Big Yellow Taxi" and "Woodstock" helped define an era and a generation. Her more starkly personal 1971 recording Blue has been called one of the best albums ever made. Musically restless, Mitchell switched labels and began moving toward jazz rhythms by way of lush pop textures on 1974's Court and Spark, her best-selling LP, featuring her radio hits "Help Me" and "Free Man in Paris."