One of England's most enduring hard rock bands, Hawkwind were formed in London during the late '60s, just as art rock was coming into its own. Though lesser known than contemporaries like Pink Floyd, the band is widely hailed as one of space rock's early pioneers, thanks to seminal albums like 1973's live opus Space Ritual, and its 1974 studio follow-up In the Hall of the Mountain Grill. Their potent mix of psychedelia, prog, straight-ahead hard rock, and lyrics steeped in science fiction -- particularly the themes and imagery of author Michael Moorcock, who also became a member at various points -- and drug effects helped define Hawkwind and separate them from the competition.