Ferdinand Tönnies was a German sociologist and philosopher, born in 1855 and known for his contributions to social theory. He is best recognized for his concepts of Gemeinschaft and Gesellschaft, which describe two types of social groups. Gemeinschaft refers to community-oriented relationships, while Gesellschaft represents more impersonal, formal associations typical of modern society. Tönnies' work emphasized the impact of industrialization on social structures and human relationships. He believed that the shift from Gemeinschaft to Gesellschaft led to a decline in social cohesion and a rise in individualism. His ideas have influenced various fields, including sociology, anthropology, and urban studies.