Social life is in a constant process of change, and sociology can never stand still. As a result, sociology today is a theoretically diverse enterprise, covering a huge range of subjects and drawing on a broad array of research methods. Central to this endeavour is the use of core concepts and ideas which allow sociologists to make sense of societies, though our understanding of these concepts necessarily evolves and changes. This clear and jargon-free book introduces a careful selection of essential concepts that have helped to shape sociology and others that continue to do so.