'… the book provides valuable information for people interested in two major theories of international relations in practice. … Schimmelfennig gives a deep insight in the process and the outcomes of NATO and EU enlargement as such and develops a theoretical approach that seems applicable to future Western organizations' enlargement decisions.' Steve Schwarzer, European Societies
'… this study is a significant and valuable contribution to the rationalist-constructivist debate in IR'. International Affairs
'Frank Schimmelfennig has steadily been making a name for himself over the years as a thoughtful and creative contributor to International Relations theory and European Studies. This work will confirm his status as a scholar of originality and insight. … this book is a model of problem-driven but theoretically informed social science. It is thorough and systematic in its treatment of the subject matter; explicit in its theoretical assumptions; and incorporates new empirical data. … an important and timely book. … His book deserves to be widely read and discussed.' European Foreign Affairs Review
'… a rich volume offering many insights. It is a credible effort to tease out something new from the examination of the two major theoretical schools of thought in IR. This book is recommended for every student of European integration theories who seeks to bridge the rationalist-constructivist divide while gaining further insights into the enlargement issue.' Journal of International Relations and Development