"A Sociology" is a combination of sociological theory and examples of its application to social development and change projects from around the world based on the author's experiences over the last thirty years. The theory of social structure is based on four dimensions and corresponding theorems on the dynamics between those dimensions. The four dimensions are intuitively grasped - Division of Labor, Solidarity, Pluralism, and Linkage - and can be applied to all levels of collectivities from groups to organizations, to communities, states, regions, countries and sectors of societies. The book is written for the medium to advanced theory course and for development practitioners with a few years experience.