The article focuses on dimensions of corporate power. Individually and collectively, large business corporations profoundly affect the U.S. society, being both the basic structural components of political economy and important influences upon essential noneconomic aspects of national life. Consequently, for nearly a century, social activists, political analysts, and ordinary citizens alike have sought to fathom the nature and consequences of corporate power in the U.S. An analytical framework for examining corporate power, its mythology and reality has been presented. Power relationships in social systems, with particular emphasis upon corporate institutions, and 3 of 6 important spheres of corporate power has been examined. The 3 remaining power spheres and the complexities of corporate political power and its ramifications for social democracy in the U.S. has been discussed. Corporate economic power underlies the other 5 spheres of corporate power. Corporations manifest the remaining aspects of power in the course of either performing their economic functions or structuring an environment conducive to undertaking these functions.