Vocalist Phil Mogg, guitarist Mick Bolton, bassist Pete Way, and drummer Andy Parker formed the British space metal outfit UFO in 1969. Originally known as Hocus Pocus, the group, which took the name UFO in honor of a London club, debuted in 1971 with UFO 1. Both the album and its follow-up, the same year's Flying, found great success in Japan, France, and Germany, but went barely noticed in the band's native country; as a result, their third effort, 1972's Live, was released only in Japan.

In 1974, Bolton left the group; after brief trial runs with ex-Pink Fairies guitarist Larry Wallis and future Whitesnake member Bernie Marsden, former Scorpion Michael Schenker stepped in as a permanent replacement in time to record 1974's Phenomenon, which sported a harder-edged guitar sound. After 1975's Force It and 1976's No Heavy Petting brought UFO increased visibility with American audiences, keyboardist Paul Raymond joined for 1977's Lights Out. However, after 1978's Obsession, Schenker left the group, first to rejoin the Scorpions and later to form his own band. Despite the addition of guitarist Paul Chapman, the next UFO LP, No Place to Run, failed to match the success of its predecessors.