Senate House Library has never been wealthy, and although its purchasing has been intended to include antiquarian books, most of its treasures have been gifts. So in the treasures volume we wanted to include at least one item that the Library had bought, as a testimony to its efforts to help itself. Thirty-seven of the Library’s 134 fifteenth-century books were in fact purchased, all between 1941 and the late 1960s. They include this edition of a monastic rule compiled by Lupo de Olmedo for the Hermits of St Jerome of the Observance. It is the latest of eight incunable editions. The edition is currently recorded in three libraries in the United Kingdom, including Senate House Library, and nineteen further copies in Europe and the United States. Thus in terms of survival it does not count as rare. But the Senate House Library copy is endeared to us by its recent provenance: the incunable collector George Dunn (1865-1912); the Oxonian ecclesiastical historian Cuthbert H. Turner; and Turner’s godson, the bookman John Carter, whose ABC for Book Collectors is held in several editions in Senate House Library.