This book represents a radical new departure for Jurgen Moltmann, not least in the lucidity of its writing. Whereas his early great trilogy, Theology of Hope, The Crucified God and The Church in the Power of the Spirit, was pragmatic, looking at theology as a whole from a particular standpoint, here he begin to consider how important concepts and doctrines of Christian theology are interrelated. However, this is not, he stresses, the beginning of a dogmatics, a systematic theology. Systems, even open systems, cannot really be discussed, and they serve as a substitute for critical and independent thought, which is fatal at a time when free dialogue and fellowship are essential for knowledge of the truth of God. So here, taking up Protestant and Roman Catholic. Western and Eastern traditions, he reconsiders the doctrine of the Trinity, with an eye especially to the overcoming of the schism which has burdened the life of the churches since 1054. At the same time, he is aware of another even older schism, that with Judaism, which also cries out for resolution if there is indeed only one God.