Paul Wilkinson is Professor of International Relations and Chairman of the Centre for the Study of Terrorism and Political Violence at the University of St Andrews, Scotland. He is joint editor of the journal Terrorism and Political Violence, and his publications include Political Terrorism, Terrorism and the Liberal State and lessons of Lockerbie. Brian M. Jenkins formerly headed RAND's terrorism research programme before moving to Kroll Associates. He was a member of the Gore Commission on Aviation Safety and Security and is now a consultant for RAND, Santa Monica.