Humans are social animals, naturally driven to form close-knit groups. All too often, though, they start to compete with one another and become mutually hostile. Why does this happen? And what can be done to counter the tendency? The authors of this book explore the shaping force of our genetic make-up on our fundamental views and the nature of the influences that family, friends and peers exert. A groundbreaking work on why people become so divided - and how they can be brought back together.