This book helps answer a fundamental question: What is the social world made of? It presents a comprehensive ontology of social entities, activities, and relations. Basic building blocks of the social world, from humans and animals to objects and cognitive entities are explored, while also posing open questions about the status of living beings. By introducing more complex social forms, such as networks and collectives, and examining how these emerge through shared resources and interactions the author applies the familiar social science notions like classes and organizations and explores life courses and causality within social phenomena. As a whole, this book offers an innovative framework for understanding the social world, inviting scholars and readers in philosophy, social sciences, and political sciences to rethink the entities and processes that shape our social reality.