The Courtauld Institute of Art, a college of the University of London, is one of the foremost centres to study art history in the UK. Like a giant Matruschka doll, the Book Library at the Institute is a specialist art library that contains within it special collections which, in turn, have individual bequests that also contain discrete rare collections. In addition to more than 7400 books catalogued online, it has a range of material that is yet to be catalogued onto the Aleph system, some of which remains inaccessible. The special collections also contain the research papers of several notable former members of staff, and a number of small archive collections that have been donated over the years. Without a dedicated reading room, the special collections feel more integrated into regular use within the library. This gives students a taste of research with historic books, but there are some inherent risks associated with such relaxed usage conditions. This article examines the origins of the Library and its place in the Institute today. It reveals the breadth of its special collections and some of its treasures, but also explains how the present funding crisis in UK higher education may harm the custodial role the Book Library has over this unique research resource.