This book examines regional economic integration in West Africa within the context of the institutional evolution of the Economic Community of West African States (ECOWAS). It uses the tools of the New Institutional Economics School to explore the origins and development of the most recent ECOWAS Treaty. Particular attention is given to the interface between domestic legal arrangements and the success of open markets at the regional and international levels. The impetus given to regional integration schemes by the belief that international economic institutions are designed to serve the interests of advanced countries is also considered.