Paul F. Diehl is Henning Larsen Professor of Political Science and University Distinguished Teacher/Scholar at the University of Illinois at Urbana-Champaign. He also serves as Director of the Correlates of War Project, the largest data-collection effort on international conflict in the world. His areas of expertise include the causes of war, UN peacekeeping, and international law. Charlotte Ku is Assistant Dean for Graduate and International Legal Studies at the University of Illinois College of Law, and Co-Director of the Center on Law and Globalization, a partnership of the American Bar Foundation and the University of Illinois College of Law. She has written and lectured widely about international law and global governance, international organisations and the teaching of international law.

"Diehl and Ku's book, particularly its focus on the normative and operating systems, contributes nicely to this growing literature on international legal change." Jacob Katz CoganUniversity of Cincinnati College of Law

• 1. Introduction; 2. A new framework for analysis and a model for legal change; 3. The influence of normative change on the operating system; 4. Extra-systemic adaptations to systemic imbalance; 5. The influence of the operating system on normative change; 6. Implications and future directions.