Social ontology is the philosophical study of the basic constitution and structure of the social world. Social ontology investigates the kinds of entities that make up the social world, its deontological structure, its relations to physical nature and mental attitudes. Social ontology thus engages a wide array of domains in philosophy and neighboring disciplines. Social and political philosophy, ethics, philosophy of mind, and metaphysics contribute to research in social ontology. Also, current social ontology is no pure armchair business. Sociology, legal theory, political science, and economics provide insights into social structures and functions that cannot be ignored by social ontology. Similarly, social psychology, history and linguistics can teach us relevant lessons about the mechanisms of establishing and overthrowing social power.