The Philosophy of Sociality examines the nature of sociality in its various forms, with special emphasis on collective intentionality. Raimo Tuomela begins with a distinction between the we-perspective and the I-perspective. His study of strong collective intentionality -- as expressed by joint intentions, collective commitment, group belief, authority-based group action, and other phenomena -- outlines the circumstances under which an individual is required to think and act as a group member. By developing a systematic theory of sociality, Tuomela investigates such topics as social institutions, cooperation, cultural evolution, and group responsibility. In The Philosophy of Sociality Tuomela asserts that we-mode collective intentionality is a conceptual prerequisite for understanding basic social notions. He finds several contexts in which we-mode intentionality is preferable to pro-group I-mode intentionality. He ultimately defends a naturalistic view of the social world by arguing that the we-mode is a genetic and cultural adaptaion.