The fall of the West German government in 1982 ended the 13-year rule of the Social Democratic Party (SPD) as the senior coalition partner under Chancellors Willy Brandt and Helmut Schmidt. In perpetual opposition from 1949 to 1966, the Social Democrats finally entered the government as the junior coalition party in 1966; three years later they assumed primary responsibility for guiding the nation. The central theme of this detailed examination of the SPD during its years of governance is that social and economic forces in the nation had a major effect, often unsettling, on the party at a time when it had achieved the pinnacle of political power. Significant changes in the party’s organization, membership, leadership, factionalism, ideology, and voter support limited its role within the political system (in the executive and legislative branches) and its influence on domestic and foreign policies. Yet, its ability to remain in power for a comparatively long period attests to its strength and respectability among the voting public. Dr. Gerard Braunthal draws on a wealth of documentation, some unpublished, located primarily in German archives and libraries. In addition, he interviewed more than 120 persons, ranging from the top SPD leaders to staff officials, members, and other specialists, to gain a greater understanding of a party that is one of the most powerful in Western Europe and in the social democratic world, and whose organization has been a model of the twentieth-century mass party.