Pettengill: Bebop jazz musicians showed their distaste for jazz classics by taking great liberties with them, as though the songs could be made interesting only through radical reshaping. Romney: Only compelling, versatile songs can stand such radical reshaping. Bebop musicians recognized this, and their revolutionary approach to the jazz classics enabled them to discover previously unknown depths in the music. Pettengill and Romney disagree over whether ['bebop musicians showed appreciation for jazz classics in radically reshaping them', 'jazz music requires musicians to adhere closely to the original version in order to be widely popular', 'bebop jazz was an improvement on the jazz classics that preceded it', 'bebop jazz was radically different from the jazz music that preceded it']