Andrew R. Johnson asks why it is the case that "believing" is centrally significant in and for Christianity. He argues that if we attend to the various implicit dimensions of explicit faith and to the holistic character of Christian believing then this central significance becomes more intelligible. The study aims to be a work of Protestant systematic theology, first and foremost, but one that is of ecumenical value. Johnson engages continental, analytic, and American pragmatic philosophers as they reflect on the human phenomenon of believing, intentional action, embodied cognition, and the relation between theory and practice. Theologically the study engages with Lutheran, Reformed, Anglican and Roman Catholic theologians as they reflect on the nature of faith in Christ amidst the concrete realities of life and the encounter with God through those concrete realities. Key interlocutors of the study include Rudolf Bultmann, Karl Barth, Cornelius Ernst, Fergus Kerr, Ludwig Wittgenstein, H.H. Price, Robert Brandom, and Andrew Inkpin, in addition to others.