Christian Meyer (CNRS), is the author of numerous books and articles on medieval music theory and, with Michel Huglo, of the catalogues of music theory, RISM B III, vols. 3-6 (1986-2003). He has edited monochord measurements (1996), treatises from the Garlandian tradition (1998), and the Musica of Hieronymus de Moravia (Corpus Christianorum, 2012). The translator, Karen Desmond (McGill University), researches the intersection between the intellectual and aesthetic experience of music in the later Middle Ages. She has published articles and reviews in Early Music History, Musica disciplina, Journal of Musicology, Journal of Plainsong and Medieval Music, Early Music, The Medieval Review and Notes. The translator of Christian Meyer’s introduction and critical notes, Barbara Haggh-Huglo (University of Maryland), has edited liturgical offices for St. Elizabeth of Hungary (1995) and the Order of the Golden Fleece (2007), and published articles on early music in Brussels, Ghent, Cambrai, and Paris, Johannes Ciconia as theorist, and, with Michel Huglo, on music theory in medieval Parisian libraries.