Understanding federalism - the form of political organization that unites separate polities within an overarching political system so that all maintain their political integrity - is central to the study of democratic government in the United States. Yet, many political scientists treat federalism as a set of abstract principles or a maze of budgetary transfers with little connection to real political life. This concise and engaging book boils the discussion down to its essence: federalism is about power, specifically the tug for power among and within the various levels of government. Author Larry N. Gerston examines the historical and philosophical underpinnings of federalism; the various change events that have been involved in defining America's unique set of federal principles over time; and the vertical, horizontal, and international dimensions of federalism in the United States today. The result is a book examining the ways in which institutional political power is both diffused and concentrated in the United States.