This book offers a systematic survey of ethos theory: the theory according to which the right sort of music can have a positive or negative effect on moral development. It also evaluates the extant empirical literature on music and moral development.The belief that the right sort of music promotes moral development is almost ubiquitous. At every stage in the history of philosophical thinking, many philosophers have believed that the right sort of music is conducive to moral improvement and the wrong kind of music can produce moral decay. This book has three main goals. The first is to inform readers about the range of thinkers and cultures (Asian, African and European) which have adopted some version of the ethos theory. The book surveys the history of ethos theory starting with its origins in ancient Greece and ancient China, proceeding to trace its development through the Middle Ages and into the early modern period. Next, the development of ethos theory is traced from the middle of the nineteenth century to the present. The second goal is to investigate what would count as evidence that ethos theory is correct, paying specific attention to the complex ways that people experience music. Finally, the author evaluates the currently available empirical evidence for ethos theory.Critique of Practical Music will appeal to philosophers, psychologists, musicologists and music educators who are interested in music and moral development.