Societal stratification phenomena are the relatively enduring, hierarchically ordered relationships of power among the units of which society is composed. The smallest units are adults, gainfully employed men and/or women, nuclear families, or sometimes extended families or households. Such units are ordered from highest to lowest in terms of power: political power, acquisitional power, the power of prestige, and the power of informational standing. Everybody experiences stratification every day, although a person often notices it only in the sense that some people seem better or worse off than he or she is. Social thinkers, powerful people, and revolutionaries have always been especially concerned with stratification.

Secure knowledge of the varying forms stratification structures may take is important because of the effects those structures have on many aspects of human experience, such as people's dreams of a better life, efforts to improve their situations, strivings for...