When Thomas Jefferson placed 'the pursuit of happiness' along with life and liberty in The Declaration of Independence he was most likely referring to Aristotle's concept of happiness, or eudaimonia. Eudaimonia is not about good feelings but rather the fulfilment of human potentials. Fulfilment is made possible by virtue; the moderation of desire and emotion by reason. The Psychology of Happiness was the first book to bring together psychological, philosophical, and physiological theory and research in support of Aristotle's view. It examines the similarity between Aristotle's concept of virtue and modern cognitive theories of emotion. It discusses the discovery of human potentials, the development of virtue and its neurological basis, the mistaken idea that fulfilment is selfish, and several other issues related to the pursuit of a good human life.