The four volumes of Neil Ker’s Medieval Manuscripts in British Libraries were published by Oxford University Press between 1969 and 1992. They comprise a catalogue of about 3,000 manuscripts in Latin and Western European vernaculars in hitherto uncatalogued or inadequately catalogued institutional collections in the United Kingdom and form a major research tool for humanist scholars. The index volume, produced under the direction of A. G. Watson, a former pupil of Ker’s and now his literary executor, and I. C. Cunningham, formerly Keeper of Manuscripts in the National Library of Scotland, provides a variety of indexes, including authors/titles; owners; geographical origins and dates of manuscripts; vernacular manuscripts; Latin and vernacular incipits; manuscripts cited; repertories cited; and iconography. There are also lists of recent accessions to libraries and of manuscripts that have migrated from one institution to another.