In the history of popular music, there are a relative handful of performers who have redefined the content of the music at critical points in history – people whose music left the landscape, and definition of popular music, altered completely. The Kingston Trio were one such group, transforming folk music into a hot commodity and creating a demand – where none had existed before – for young men (sometimes with women) strumming acoustic guitars and banjos and singing folk songs and folk-like novelty songs in harmony. On a purely commercial level, from 1957 until 1963, the Kingston Trio were the most vital and popular folk group in the world.