In this revised and updated version of his popular history, Justo González retains the essential elements of his earlier three volumes as he describes the central figures and debates leading to the Councils of Nicea and Chalcedon. Then he moves to Augustine and shows how Christianity evolved and was understood in the Latin West and Byzantine East during the Middle Ages. Finally, he introduces the towering theological leaders of the Reformation and continues to trace the development of Protestant, Catholic, and Orthodox Christianities through modernity in the twentieth century to postmodernity in the twenty-first.