This book is about the social life of monkeys, apes and humans. The central theme is the importance of social information and knowledge to a full understanding of primate social behavior and organization. Its main purpose is to stress evolutionary continuity, i.e. that there are direct connections between human and nonhuman society. This view is often downplayed elsewhere in the anthropological literature where the notion that humans have culture and animals do not is prevalent. Topics covered include an overview of the contexts of behavior; a comparison of blind strategies and tactical decision-making; social cognition; a review of intentionalist interpretations of behavior; kinship; language and its social implications; and the constraints of culture.