This book explores the role of music in an early fourteenth-century French manuscript. It sets the manuscript against the wider culture of Parisian book-making, showing how in devising new systems of design and folio layout, its creators developed a new kind of materiality in music. It also illustrates how music is expressive in ways that are unperformable apart from its visual representation, and argues that the new attitudes to material music making embodied in the manuscript serve as a model for exploring other music manuscripts to emerge in late medieval France.