The marvellous, a key concept in literary debates at the turn of the seventeenth century, involved sensory and perspectival transformation, a rhetoric built on the unexpected, contradictory, and thought-provoking. The composer Claudio Monteverdi (1567–1643) created a new practice in which the expressive materials of music and poetry were placed in concert. This innovative new study of Monteverdi's literary personality integrates musical and poetic analysis to create an approach to text-music relations that addresses scholars of both literature and music. It illuminates how experiments in language and perception at the turn of the seventeenth century were influenced and informed by the work of musicians of that era. Giles provides a new perspective on the music and poetry of Monteverdi's madrigals through the poetics of the marvellous. In his madrigals, Monteverdi created a reciprocity between poetry and music which encouraged audiences to contemplate their interactions, and, consequently, to listen differently.