No matter what we do, however kind or generous our deeds may seen, a hidden motive of selfishness lurks - or so science has claimed for years. This book tells readers differently. The authors demonstrate that unselfish behaviour is in fact an important feature of both biological and human nature. Their book provides a panoramic view of altruism throughout the animal kingdom - from self-sacrificing parasites to insects that subsume in the superorganism of a colony to the human capacity for selflessness - even as it explains the evolutionary sense of such behaviour. Explaining how altruistic behaviour can evolve by natural selection, this book gives credence to the idea of group selection that was originally proposed by Darwin but denounced as heretical in the 1960s. It takes an evolutionary approach in explaining the ultimate psychological motives behind unselfish human behaviour. Developing a theory of the proximate mechanisms that most likely evolved to motivate adaptive helping behaviour, the authors show how people and perhaps other species evolved the capacity to care for others as a goal in itself.