Jacqueline Edmondson's 2013 encyclopedia "Music in American Life" states that, although it was preceded by earlier examples, Frank Zappa and the Mothers of Invention's debut album "Freak Out!" (June 1966) came to be seen as "the first successful incorporation of art music in a pop context". With Los Angeles as his base since the early 1960s, Zappa was able to work in an environment where student radicalism was closely aligned with an active avant-garde scene, a setting that placed the city ahead of other countercultural centres at the time and would continue to inform his music. Writer and pianist Michael Campbell comments that the album "contains a long noncategorical list of Zappa's influences, from classical avant-garde composers to obscure folk musicians".