Milton and Music is the first study to juxtapose John Milton's poetry on music with later musical adaptations of his work. In Part I: Milton on Music, Seth Herbst shows that writing about music galvanized Milton's intellectual development towards animist materialism, the belief that everything in the universe--even the human soul--is made of matter. The Milton who emerges is a forward-thinking visionary who leaped past his contemporaries in conceiving music as a material phenomenon that exists simultaneously as sound and metaphor. Part II: Milton in Music follows two daring composers in investigating whether Milton's visionary concept of music can be realized in actual musical sound. In Samson, an oratorio adaptation of Milton's Samson Agonistes, Handel resists Miltonic music theory, suggesting that music struggles to function as both sound and metaphor. By contrast, the twentieth-century Polish composer Krzysztof Penderecki composes an iconoclastic opera of Paradise Lost that develops a soundworld of fractured dissonance in which music acts as both sound and metaphor. Recovering Milton's own high estimation of music from a critical tradition that has subordinated it to the poet's political and religious convictions, Herbst reveals Milton as an interdisciplinary thinker and overlooked figure in the study of words and music. Driven by bold claims about the comparative treatment of literature and music, Milton and Music revises our understanding of what makes this canonical poet an intellectual revolutionary.