Human friendship has been millions of years in the making, and evolutionary science richly reveals that deep history. Yet close friendship is a puzzle to evolutionary scientists because they misconstrue close relationships in strictly means-ends terms. Although social science offers sophisticated methods, it is limited by impoverished theory imbued with the unacknowledged assumptions of individualism and instrumentalism. In this book, Blaine Fowers argues that such egocentric and instrumental portrayals are not only erroneous--they also undermine good relationships. Flourishing and Friendship presents an interdisciplinary theory of friendship that draws on psychological science, Aristotle's theory, evolutionary science, attachment science, and identity theory. It is informed by historical, cultural, and philosophical perspectives on close relationships. Aristotle's concept of virtue friendship offers theoretically rich solutions to the difficulties plaguing social scientists today, but his conceptual framework can be significantly enhanced with the ample content of evolutionary science, attachment science, and identity theory, as well as the powerful methods of social science. For example, evolutionary and attachment sciences bolster the nature fulfillment basis of Aristotle's ethics. Friendship can be fruitfully framed as a type of attachment. Identity theory contextualizes friendships in social networks and cultures. Fowers put these various perspectives into conversation to produce an integrated theory of friendship. This theory recasts the too familiar and inadequate contemporary Western concept of friendship into a uniquely evolved capacity for inherently valuable and shared activity in the service of a good human life.