While the question “Is faith reasonable?” has continually occupied philosophers and theologians, little attention has been paid to what faith itself is. The Act of Faith remedies this neglect by looking at what it means for a person of Christian faith to believe. Eric Springsted contrasts modern views of faith with the Christian tradition running from Augustine through Aquinas and Calvin. Drawing on contemporary philosophers and theologians like John Henry Newman and Simone Weil, Springsted builds a fresh understanding of faith for today. He shows how the “inner act” of faith is ultimately a radical willingness to be open to God, and he argues that the faithful self is one that develops within a community that shapes its members through the morally formative activities of interaction, teaching, and sacramental practice.