Hardback with green cloth boards and titles in gilt to spine in very good condition. Spine lightly bumped top and bottom and indentation at top of front board and middle of rear board. Top of textblock slightly tanned. A few notes in pencil throughout text. A verse from Samuel Butler\'s preface to his cantata Narcissus inscribed in pencil on ffep by previous owner. Illustrated with 88 black and white facsimile scores, throughout the text. Bibliographic footnotes. Commentary and index at the end, followed by an appendix (transcriptions). Publication no. 38 of The Medieval Academy of America. Fifth edition, revised.