Among distinguished sociologists, Charles Horton Cooley was an American sociologist. Cooley refused to label himself a sociologist, and sought to merge history, philosophy, and social psychology. Charles Horton Cooley is best known for his concept of the looking glass self, a concept that a person's self grows out of society's interpersonal interactions and also the perceptions of others. The way in which the individual's sense of self is 'mirrored' and reflected through others. Cooley's The Theory of Transportation (1894), was noted for its conclusion that towns and cities tend to be located at the confluence of transportation routes, the 'break in transportation'. In Human Nature and the Social Order (1902) he detailed the way in which social responses affect the emergence of normal social participation.
Cooley extended the concept of the "looking-glass self" in Social Organization (1909), in which he sketched a comprehensive approach to society and its major processes. Cooley's 'primary group', characterized by close, intimate, face-to-face interaction, contrasted with the larger and more disparate 'nucleated group' or the 'secondary group', whose members were rarely in direct contact. Charles Horton Cooley was a founding member of the American Sociological Association.