Daniel Nettle is Professor of Behavioural Science at Newcastle University. His varied research career has spanned a number of topics, from the behaviour of starlings to the origins of social inequality in human societies. His research is highly interdisciplinary and sits at the boundaries of the social, psychological and biological sciences. Daniel has published seven previous books, including Vanishing Voices (with Suzanne Romaine); Strong Imagination: Madness, Creativity and Human Nature; Happiness: The Science Behind your Smile; and Personality: What Makes You the Way You Are. Daniel has served as President of the European Human Behaviour and Evolution Association, a council member of the Royal Anthropological Institute, and an editor of the journals Evolution and Human Behavior, Evolution, Medicine and Public Health, and the Proceedings of the Royal Society, B.