From the thirteenth and more especially the fourteenth century, the papacy assumed an increasingly important role in making appointments to ecclesiastical benefices. Papal provisions indeed are one of the most conspicuous features of the machinery of papal government in the two centuries prior to the Reformation. None the less, certain aspects of the operation of papal provisions remain obscure. This applies perhaps above all to the appointment and activities of the men responsible for ensuring that the terms of the letters of provision were implemented, that is, the executors. The latter were nominated by the provisors and enjoyed considerable powers. The present volume, based on Kirsten Hitzbleck's Cologne doctoral dissertation, supersedes all earlier work on the subject, and is likely to remain the standard treatment of it for many years to come. Although it concentrates on the pontificate of John xxii (1316–34), its conclusions are of importance over a much longer period. It begins with two subtle and carefully argued chapters on the canonistic doctrine of executors from the twelfth century onwards. The heart of the book is the long third chapter on the various stages of the legal process instituted by executors. This is followed by a chapter on executors and sub-executors. Chapters v and vi concern the selection of the two main types of executors, those resident in the papal curia and those acting in partibus. The final chapter discusses motives in the choice of executors. One of the principal conclusions is that provisors had a wide measure of freedom in nominating executors and in many cases were thus able to choose men who were favourably disposed towards them. The impact of papal provisions was felt throughout Latin Christendom, even though unevenly, and a comprehensive geographical treatment of their executors would be impracticable. Instead the author pays particular attention to southern France and the ecclesiastical provinces of Cologne, Trier and Rheims, and she provides a series of illuminating case studies. One topic not covered by Hitzbleck is what payment (if any) the executors received for their labours. It would be interesting to know whether she has uncovered any evidence concerning this. There are a few minor slips and misprints, and the book is somewhat marred by the hypercritical tone adopted towards those historians (notably Geoffrey Barraclough) who have had the misfortune to address the subject prior to the author, but in other respects it is a most impressive achievement.