The sudden and dramatic democratization of Eastern Europe during 1989-90 was something that had not been predicted by political scientists. This text is a response to those events, in that it seeks to provide some theoretical explanations for the process of democratization in Eastern Europe and compare that experience with the democratic transitions experienced in other parts of the world. The contributions focus on the causal factors of democratization and are organized into three main sections. In the first, the process of democratization is analyzed from the domestic perspective of the countries concerned and this approach includes the investigation of long-term structural changes and historical factors. In the second, attention is focused on the struggles of social and political structures and on the emergence of multi-party and new electoral systems. The final part investigates how far democratization was influenced by external factors and considers in particular the role of reform in the Soviet Union under Gorbachev and the appeal of Western social, political and economic systems.