This study surveys post World War II efforts to enhance practical cooperation among European countries in the provision and use of military forces. The author, a distinguished former defense official of the U.K., begins with the earliest proposals for cooperation in 1947 and provides a succinct summary of collective security efforts since then. The main focus of the study is the European Defense and Security Policy (EDSP) project launched by European Union heads of government at their Cologne meeting in June 1999. Quinlan reviews the major issues and future prospects regarding this important initiative, and argues for a collective European defense that will complement but not supersede the role of NATO. European Defense Cooperation is the first title in the Wilson Forum series from Woodrow Wilson Center Press.