This book is one of the first systematic attempts to bring language within the neo-Darwinian framework of modern evolutionary theory, without abandoning the vast gains in phonology and syntax achieved by formal linguistics over the past forty years. The contributors - linguists, psychologists, and paleoanthropologists - address questions including: What is language as a category of behaviour? Is it an instrument of thought or of communication? If the latter, how does it differ from other systems of animal communication? What do individuals know when they know a language? What cognitive, perceptual, and motor capacities must they have to speak, hear, and understand a language? For the past two centuries scientists, as children of societies preoccupied with technology, have tended to see language function as largely concerned with the exchange of practical information about the mechanics of the physical world: toolmaking, hunting, and so forty. By contrast, this volume (a product of the age of mass democracies) takes as its starting point the view of human intelligence as social, concerned with one's own and others' desires and motives, and of language as a device for forming alliances, making friends, and thus achieving successful feeding and mating through a complex social network. From this perspective, phonologists and syntacticians may explore the origins of the sound patterns and formal structures that characterize all language.