Prologue -- Part one. Social behavior. Primate diversity -- Barbary macaques : model monkeys -- Primate social systems -- Chacma baboons : into the wild -- Guinea baboons : uncharted territories -- The evolution of baboons -- Challenges of the third kind -- Part two. Cognition. What do animals think? -- Physical cognition -- Social intelligence -- Social knowledge -- Theory of mind -- The evolution of intelligence -- Part three. Communication. What is communication? -- The function of monkey sounds -- The evolution of language : beginnings -- Ape language projects -- Natural communication in primates -- Word learning in a domestic dog -- The evolution of language : state of the art -- The evolution of communication -- Conclusion and prospects.