The collection of essays under review is securely situated within a rigorous primary source studies approach (or "positivistic" approach, as it is now fashionably derided), although some reflection on Cousse - maker's role in the creation of the "canon" of medieval music history is also apparent, most notably in the essays of Ronald Woodley and Nils Holger Petersen. The authors review the books listed in the library catalogues of the grand abbeys of the North, such as Saint-Amand, Corbie and Anchin (mostly books on musica speculativa); those of the cathedrals and large collegiate churches such as Cambrai that flourished later on (where liturgical books and books on musica pratica dominate); and they end with a discussion of the libraries of some important individuals: of particular interest, of course, is the booklist belonging to Du Fay.