German Reformed theologian. His faith and theological perspectives were influenced by his experiences as a British prisoner-of-war from 1945 to 1948. He held various academic posts; from 1967 until his retirement he was a professor at Tübingen. He is best known for three books translated into English as Theology of Hope (Eng. tr., 1967), The Crucified God (Eng. tr., 1974), and The Church in the Power of the Spirit (Eng.tr., 1977), which were followed by works on messianic theology and eschatology. His understanding of God is characterized by Divine passibility (in contrast with the traditional notion of impassibility) and social trinitarianism. The Divine Persons are seen as involved in a history of mutual relationships with the world.