The linkage between nationalism, or to be more precise ethnonationalism, and international relations is now at the center of world politics. Following years in which this dimension has been neglected in our literature, the discipline has finally caught up with the reality that most of the conflicts taking place around the world are related to the politics of national or ethnic identity. To be sure, political science responded earlier to the call of Walker Connor (“Nation Building or Nation Destroying,” World Politics 24 [April 1972]: 319–55) and Anthony Smith (The Ethnic Revival 1981) to supplant the notion of the integrated modern state with a more pluralistic approach. Following the end of the Cold War, international relations as a discipline had no choice but to pay attention to ethnicity. As expected, once the phenomenon was recognized, the literature grew extensively in both the theoretical and empirical areas. In recent years, even Michael Brecher's and Jonathan Wilkenfeld's prestigious International Crisis Behavior (ICB) worldwide data set had to turn around and adopt an ethnic variable. Patrick James and David Carment, using the ICB empirical stockpile, dedicated a large portion of their work to the ethnic dimension of international crises. Similarly, T. R. Gurr, also a former president of the International Studies Association (like Brecher), made an about-turn and focused his work on conflict through his Minorities At Risk (MAR) database on ethnicity. Kristen Williams's book is thus another attempt to integrate international relations theory and ethnic politics literature while basing it on empirical research. Despite some flaws, this book should be welcomed into the growing literature on nationalism and international conflict. It has two theoretical and four empirical chapters, each covering a different case, starting with Bismarck and German unification and proceeding to Bosnia, Kosovo, and Kashmir.