This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book examines the continuity and change in three dimensions of the Soviet-East European relationship--multilateral institutional ties, bilateral agreements, and informal arrangements--over a twenty-year time span. It addresses the issue of East Europe's Westpolitik, but with a more narrow focus on the sources and substance of East German behavior. The book also examines the costs of Soviet economic policies toward Eastern Europe, explains why the Soviet Union in the past chose to subsidize the other Council of Mutual Economic Assistance states, and analyzes the reasons why the Soviets want a change. It focuses on Soviet-East European relations during the first three years of the Gorbachev era. The book shows that while responses in Eastern Europe to Gorbachev's initiatives vary significantly from country to country, they exhibit a number of common features.