This commentary focuses on the four major writings of our Holy Carmelite Father, St. John of the Cross. He rightfully enjoys throughout Holy Mother, the Church, not only the title of Doctor of Mystical Theology but also the reputation of being a most august and excellent mystagogue among all of the Church's mystics. The key to our Holy Father's mysticism is the cross of Christ with its triune cruciformity. The vertical beam embraces the eternal/temporal order of the universe's existence; the horizontal beam spans the historical order of the world's resistance beginning with the Book of Genesis and the world's future end culminating eschatologically in the Last Judgment. The third order is the cross's cruciformity consistently reconciling these two vertical and horizontal beams together in the Paschal Mystery of Jesus Christ's crucifixion, resurrection, ascension, and Parousia, final return in glory.