In this chapter, I introduce and evaluate versions of existential authenticity, advanced by Friedrich Nietzsche, Martin Heidegger, Soren Kierkegaard, Jean Paul Sartre, and Albert Camus. I conclude that the varieties of existential authenticity, taken collectively, evince numerous insights: They deny the existence of an antecedently given true self that might provide guidance to human choice and action; they insist on recognizing freedom and responsibility, and minimizing resorting to excuses when evaluating actions; they distance the individual from the false necessities of dominant ideas and fixed social conventions; they advocate that we create our identities through our deliberations, choices, and actions under conditions of radical uncertainty; and they concede that a measure of faith is required for vibrant living. Nevertheless, we should be cautious about wholesale enthusiasm. I sketch criticisms of the ideal of authenticity that demonstrate the ideal’s fragility. Then I add my own suspicions. Still, if authenticity is not everything, to conclude that it is nothing is unwarranted.