Renowned guitarist and composer Frank Zappa was amongst the most influential, innovative, and controversial artists of the past twenty years. His music grew from a variety of musical sources, including rock, jazz, blues, and the classical repertoire. An admirer of Edgar Varèse, Igor Stravinsky, and Anton Webern, Zappa initiated many of his listeners to sounds generally associated with "serious," twentieth-century music such as dissonant harmony, complex rhythms, and novel instrumentation. He consistently treated these aspects of music with a sense of humour and shaped them through a predilection for the absurd. Zappa composed symphonic works that were performed and recorded by various orchestras, including the London Symphony Orchestra, and the Ensemble Inter-Contemporain (conducted by Pierre Boulez).