Notable artists and musicians such as Nam June Paik and Elvis Presley, Karlheinz Stockhausen and the Beatles, Peter Roehr and Andy Warhol, Terry Riley and Ken Kesey worked with loops in the post-World War II era—short sequences of sound or images repeated with the help of recording media. By utilizing this remarkably flexible and versatile aesthetic tool, they achieved very different aesthetic results. Loops can be considered one of the most important aesthetic design elements of postmodern aesthetics, yet they have largely been overlooked as an aesthetic phenomenon. This book narrates for the first time their evolution from a technical malfunction to the foundation of entire subcultures—such as the techno and hip-hop scenes—thus telling a hidden history of culture in the second half of the 20th century.