This book is a philosophical study of the content of mental representations of music. The central problem it addresses is as follows: how is it possible to describe a listener's cognition using music-theoretic concepts the listener does not possess? The author explains what it is for music cognition to be nonconceptual and how such mental representation contrasts with conceptual thought. The author is both a philosopher and a musicologist and uniquely combines the perspectives of both disciplines. Exploring philosophical questions of mental representation in the relatively neglected, non-verbal domain of music, this study is a major contribution to the philosophical understanding of music perception and cognitive theory.