Jethro Tull are a British progressive rock band formed in Blackpool, Lancashire, in 1967. Initially playing blues rock and jazz fusion, the band soon incorporated elements of English folk music, hard rock and classical music, forging a signature progressive rock sound. The group's lead vocalist, bandleader, founder, principal composer and only constant member is Ian Anderson, who also plays flute and acoustic guitar. The group has featured a succession of musicians throughout the decades, including significant contributors such as guitarists Mick Abrahams and Martin Barre ; bassists Glenn Cornick, Jeffrey Hammond, John Glascock, Dave Pegg, Jonathan Noyce and David Goodier; drummers Clive Bunker, Barrie "Barriemore" Barlow and Doane Perry; and keyboardists John Evan, Dee Palmer, Peter-John Vettese, Andrew Giddings and John O'Hara.

Progressive rock is a broad genre of rock music that primarily developed in the United Kingdom through the mid- to late 1960s, peaking in the early 1970s. Initially termed "progressive pop", the style was an emergence of psychedelic bands who abandoned standard pop traditions in favour of instrumentation and compositional techniques more frequently associated with jazz, folk, or classical music. Additional elements contributed to its "progressive" label: lyrics were more poetic, technology was harnessed for new sounds, music approached the condition of "art", and the studio, rather than the stage, became the focus of musical activity, which often involved creating music for listening rather than dancing.