Tangerine Dream bootleg recordings are performances by Tangerine Dream that have attained some level of public circulation without being available as a legal release. The term most often refers to audio recordings, but also includes video performances. Bootleg recordings arise from a multitude of sources, including covertly copied live concerts, studio outtakes, broadcast performances. Some bootlegs have included material from official releases. Keen Auricle is another fan project, but they did not have permission from the band and so are considered bootlegs.