Raimo Tuomela, late Professor Emeritus at the Centre for Philosophy of Social Sciences (TINT), University of Helsinki, is widely regarded as one of the most important philosophers of our time. He published extensively on various topics within social philosophy; particularly, on social action, cooperation, group belief, group responsibility, group reasoning, social practices, and institutions. To celebrate his legacy, this volume engages with and delves deeply into his philosophy of sociality. By gathering original essays from a world-class line-up of social ontologists, social action theorists, and social philosophers, this collection provides the first comprehensive and critical treatment of Tuomela's outstanding contribution to social ontology and collective intentionality.