Sally Harper is senior lecturer in the School of Music at Bangor University, Wales, and an associate chaplain of Bangor Cathedral. She has written widely on music and culture in medieval and early modern Wales, and on medieval liturgy.

P.S. Barnwell is Fellow in the Historic Environment at Kellogg College, University of Oxford, UK. His research interests include the relationships between theology, liturgy, lay devotion, and the evolution of the form of the English medieval parochial church.

Magnus Williamson is senior lecturer at Newcastle University. His research focuses on the sources and contexts of Tudor polyphony, organs, improvisation, and critical editing. He is currently General Editor of the British Academy series Early English Church Music.

John Harper, though not one of the editors, is the principal author, and has been the fons et origo of the practice-led research project from which this book flows and which exemplifies his career as a liturgical musician, scholar, teacher and administrator. Through honorary association with the University of Birmingham, UK, and emeritus associations with Bangor University and The Royal School of Church Music, he continues his work in sacred music studies and liturgy. He is perhaps most widely known for his useful guide The Forms and Orders of Western Liturgy from the Tenth to the Eighteenth Century.