Chapter 5 delves deep into the issue of social evolution. This is a multifaceted topic with many distinct perspectives — some complementary others competitive. It is difficult to find a good account of these in a single source, hence the treatment here aims to be synthetic. It entails an account of how social behaviour and interactions have evolved in different species, as well as an explanation of how social behaviour affects, and is affected by, the course of evolution. The fierce debate on sociobiology is recaptured, with special attention given to such different super-social species as insects and primates, while also considering other groups of species. This is followed by an examination of the evolution of empathy, morality and altruism in primates and humans, resulting in human sociobiology and its modern equivalent evolutionary psychology. Both criticism and defence of it will receive attention. The chapter closes with reviewing the many facets of the evolution of human language(s), which has been intricately linked to the evolution of ultra-sociality in humans.