A number of words of appreciation are in order. I would like to thank the President and Fellows of Harvard College for permission to reprint segments of two articles that appeared in The Harvard Theological Review, the Medieval Academy of America for permission to reprint segments of a paper that appeared in Speculum, and Picard for permission to reprint segments of a study that appeared in Les Juifs au regard de l'histoire: Mélanges en l'honneur de Bernhard Blumenkranz. A number of colleagues and friends read drafts of this study and readily shared their knowledge and wisdom with me. My warmest appreciation goes to Professors David Berger, Robert I. Burns, Gavin I. Langmuir, Norman Roth, and Joseph Shatzmiller. They are of course in no sense responsible for the shortcomings of this final product. The staff of the University of California Press has once more been most concerned and helpful. My special thanks to Stanley Holwitz, Shirley Warren, and Sheila Berg. Finally, my deepest debt is owed, as always, to my wife and children, who have for so many years staunchly supported this and similar projects.