David Crouch is professor of medieval history at the University of Hull. He is an aurthority on twelfth-and thirteenth-century English and Norman history. His works on aristocracy include: The Beaumont Twins (Cambridge, 1986); The Image of Aristocracy in Britain, 1000-1300 (Routledge); William Marshal (2nd edn, Longman). He has also published The Reign of King Stephen, 1135-1154 (Longman) and The Normans: the History of a Dynasty (Hambledon).