Who Governs? Democracy and Power in an American City by American political theorist Robert A. Dahl was a game-changer when it was first published in 1961, and remains one of the most influential books ever written in the field of political science.

Here Dahl argues that American liberal democracy is a pluralist system in which policy is not, as you might think, shaped by a small group of powerful individuals. Rather, power is distributed among a number of competing groups, with each of these groups seeking to influence decisions.

Dahl provides evidence for this by making a case study of the decision-making process in New Haven, Connecticut, where only the mayor has power in all areas. The city’s “highly competitive two-party system” leads Dahl to view the entire United States as New Haven writ large.

Who Governs? is a key text of pluralist democratic theory, the thinking that dominated the way America studied the notion of power in the late 1950s and 1960s.