The Great Theologians: A Brief Guide (IVP Academic) by Gerald McDermott is a useful and readable guide to the key thinkers who helped shape the way the church thinks about Christian theology. Taking on 11 major theologians: Origen, Athanasius, Augustine, Aquinas, Luther, Calvin, Edwards. Schleiermacher, Newman, Barth and Von Balthasar — the author provides for each a biographical sketch, an overview of their key ideas and a brief selection from their writings.