As the sequel to Groups: The Evolution of Human Sociality (2013), this book has broadened the discussion to examine the actions of people, apes, and monkeys in terms of 'what they do' by forming groups or in-groups. In Institutions, the shared processes and practices that facilitate coexistence in groups are examined from an evolutionary historical perspective. Contributors include researchers from the field of anthropology, including sociological primatology, ecological anthropology, and sociocultural anthropology. The chapters examine institutions from a diverse range of perspectives, including: encountering death, children's games, conflict and peace, cattle rustling, and mathematical proofs. In terms of non-human primates, this study focuses on 'pre-institutional' phenomena, such as relations established through 'call and response' patterns and food sharing, and it forms arguments as to whether the concept of institutions can be applied to these settings. As the chapters in this volume establish, the argument that language is a prerequisite for the establishment of institutions has indeed been surpassed.