Book excerpt: Von Balthasar presents one of the few serious studies available on the thought of one of the most important, and yet most neglected Fathers of the Church, Gregory of Nyssa. He was the most profound Greek philosopher of the Christian era, a mystic and an incomparable poet whom St. Maximus designated as the "Universal Doctor" and the Second Council of Nicaea declared him "Father of Fathers." Less prolific than Origen, less cultivated than Gregory Nazianzen, less practical than Basil, Gregory of Nyssa nonetheless outstrips them all in the profundity of his thought, for he knew better than anyone how to transpose ideas inwardly from the spiritual heritage of ancient Greece into a Christian mode.