This document provides an overview of sociology, discussing its key concepts and early influential thinkers. It defines sociology as the scientific study of social behavior and human groups, focusing on social relationships and how societies develop and change. It describes the sociological imagination and distinguishes sociology as a social science. The document then profiles influential early sociologists like Comte, Martineau, Spencer, Durkheim, Weber, Marx, DuBois, and Cooley and their major contributions to establishing sociology as a discipline.