Specification for a Bestseller

Books of Hours in the late medieval Low Countries were typically produced in modular form, with specialised craftsmen handling different stages of production — parchment preparation, copying, rubrication, illumination, and binding. A single parchment leaf, once reused as a pastedown and now kept at the Museum Huis van het boek in The Hague (MS 10 A 10, 58f), offers rare insight into the (commercialised) process of book making. The recto contains the beginning of the Hours of the Virgin in Middle Dutch, likely intended as a sample page for prospective clients. In the lower margin, a production specification outlines the planned content, structure, materials, and cost of a custom Book of Hours. These scribbled notes shed unique light on the role of the librarius — a bookseller acting as an intermediary between producer and client — and illustrate the modular approach to producing a Book of Hours in the Low Countries during the second half of the fifteenth century.