International organizations have once more become subjects of investigation for a whole range of scholars: political scientists, international relations specialists, organization theorists, and policy experts alike. The end of the Cold War, increased globalization, and the intensification of regional and functional cooperation all have produced a greater interest in the role of international organizations, and rightly so, since they increasingly take part in global governance as over-burdened governments become more and more willing to transfer responsibility to them or need to work through them. International Organizations and Policy Implementation determines the extent to which international intergovernmental organizations are involved in the national implementation of internationally formulated policies. In particular, it specifies the conditions under which they can be more or less successful in influencing the course and content of implementation or imprint their perspective on domestic policies. This edited volume helps to fill a gap in the existing literature in two respects: contrary to many implementation studies, the chapters are comparative in nature contrasting the role of international organizations across time, different levels, or different issue areas; and, second, they are theoretically grounded.