Robert O. Keohane has been one of the most innovative an influential thinkers in international relations for more than three decades. His groundbreaking work in institutional theory has redefined our understanding of international political economy. This work is a collection of his most recent essays that address such core issues as interdependence, institutions, the development of international law, globalization and global governance. The essays are placed in historical and intellectual context by a substantial new introduction outlining the developments in Keohane's thought. In an original afterword, the author offers a challenging interpretation of the September 11th attacks and their aftermath.