This document discusses how society is organized into social groups. It defines social groups as collections of interdependent individuals who share goals and values. Primary groups are small, intimate groups whose members interact closely over long periods of time, while secondary groups are larger and more specialized with impersonal, objective-focused interactions over shorter times. Reference groups are groups people compare themselves to in order to guide their behaviors and attitudes. Social networks refer to the sets of relationships between individuals or groups within a society.