The essays in this book provide new insights into the history of heresy and the formation of the persecuting society in the Middle Ages and explores the shifting understanding of orthodoxy and heterodoxy in medieval and modern times.

Michael Frassetto, Ph.D. (1993) in History, University of Delaware, is religion editor at Encylopaedia Britannica. He has published numerous works on heresy and Ademar of Chabannes and edited the volume The Year 1000.