The Incredible String Band were a British psychedelic folk band formed by Clive Palmer, Robin Williamson and Mike Heron in Edinburgh in 1966. The band built a considerable following, especially in the British counterculture, notably with their albums The 5000 Spirits or the Layers of the Onion (1967), The Hangman's Beautiful Daughter (1968), and Wee Tam and the Big Huge (1968). They became pioneers in psychedelic folk and, through integrating a wide variety of traditional music forms and instruments, in the development of world music.

Psychedelic folk is a loosely defined form of psychedelia that originated in the 1960s. It retains the largely acoustic instrumentation of folk, but adds musical elements common to psychedelic music.