By the end of the Middle Ages, the abbey at Canterbury founded by St. Augustine possessed one of the most worldly and richest libraries in all of Britain. The remarkably sophisticated catalog produced by its medieval librarians, dating from the late fourteenth century, provides detailed entries for over 1,800 volumes, reporting a press mark, table of contents, and donation record for each—as well as internally cross-references for each entry. The wealth of the library, both in size and scope, is reflected in the three magnificent volumes of St. Augustine’s Abbey, Canterbury which presents the first fully annotated edition of this extraordinary catalog and illuminates the clearest picture yet of one of the great libraries of medieval Britain.