This study is concerned with describing and analyzing the factors that led to the election and subsequent defeat of Salvador Allende. The research information was selected from leading books, periodicals, government documents, archives, and newspapers. The thesis presents the political history of Allende's rise to power, the social structure that made his victory possible, the development of major programs that facilitated his ascension and that made his decision inevitable, and, finally, an analysis of his administration with observations as to why he failed. The importance of the lower class, the middle class, the military, and the United States are presented as factors contributing to Allende's victory and later accelerating Allende's fall from power.