Robert A. Dahl (1915), American political scientist, sociologist, leading expert on the theory of democracy, professor emeritus at Yale University, analyses in this book the key criteria, procedures, material and psychological constraints and obstacles in the movement of societies towards political equality. A special place in the analysis is given to the role of natural and genetic properties of humans as a species, moral and ethical motivations and emotional reactions that determine people’s desire for political equality as a means of overcoming injustice and achieving individual and collective well-being.