'Karen Desmond's book places early fourteenth-century music and musical thought persuasively within their intellectual contexts. Equally at home in music theory, the history of musical style, palaeography, prosopography, astronomy, philosophy and a whole host of other fields of knowledge, she rises to the challenge of saying something substantially 'new' about the ars nova. Drawing all these intellectual threads masterfully together, Desmond's breath taking study will be the defining work on the subject for many years to come.' Christian Thomas Leitmeir, University of Oxford