How did we become the linguistic, cultured, and hugely successful apes that we are? Our closest relatives - the other mentally complex and socially skilled primates - offer tantalizing clues. In this volume nine of the world's top primate experts read these clues and compose the most extensive picture to date of what the behaviour of monkeys and apes can tell us about our own evolution as a species. This text gives us the latest news about bonobos, the "make love not war" apes who behave so dramatically unlike chimpanzees. We learn about the tool traditions and social customs that set each ape community apart. We see how DNA analysis is revolutionizing our understanding of paternity, inter-group migration, and reproductive success. And we confront intriguing discoveries about primate hunting behavior, politics, cognition, diet, and the evolution of language and intelligence that challenge claims of human uniqueness in new and subtle ways.