In the discussion of the sociological and political science research on the unification of Germany the positions range from the view that intra-German transformation has been successful on the whole and that it has begun to stabilize to contentions that eastern Germany has been colonized by western German actors and that Germany’s unification has failed. Between these two poles lie arguments calling attention to newly emerging differences between eastern and western Germany. Critically reviewing assessments of German unification, I come to four conclusions. First, the social science discussion about the topic is divided into two debates. One of them is centered on the controversy between the modernisation thesis and assertions by skeptics and critics. The other debate is focused on the problems of controling intra-German transformation. Second, the discussion is largely isolated from research on transformation underway in eastern and central Europe at large. Third, the evaluation of the process, impacts, and perspectives of German unification is affected by the theoretical position of the researchers and the methodological design of their studies. Fourth, the future development of social science research on German unification is being determined by two trends, internationalization and regionalization.