What makes us human? How did we develop language, thought and culture? Why did we survive, and other human species fail? Robin Dunbar is an evolutionary psychologist and former director of the Institute of Cognitive and Evolutionary Anthropology at Oxford University. His acclaimed books include How Many Friends Does One Person Need? and Grooming, Gossip and the Evolution of Language, described by Malcolm Gladwell as 'a marvellous work of popular science.'