JOHN HALDON is Professor of History at Princeton University, USA. He studied in the UK, Greece and Germany, and is a Senior Fellow at the Dumbarton Oaks Center for Byzantine Studies in Washington D.C. His research focuses on the history of the early and middle Byzantine empire, in particular in the period from the seventh to the eleventh centuries; on state systems and structures across the European and Islamic worlds from late ancient to early modern times; and on the production, distribution and consumption of resources in the late ancient and medieval world, especially in the context of warfare. His publications include Byzantium in the Seventh Century (CUP: 1990/1997), Three Treatises on Byzantine Imperial Military Expeditions (Austrian Academy: 1990), The State and the Tributary Mode of Production (Verso: 1993), Warfare, State and Society in Byzantium (Macmillan 1999), Byzantium: a History (Tempus: 2000) and The Social History of Byzantium (Blackwell 2009).