Theology is, for the sake of its own clarity, dependent on a notion of God's hiddenness and unknowability. This is a position that over the years has been maintained by a number of theologians and philosophers. Even within the Christian tradition, which understands God as manifest in the person of Jesus, the perspective of negative or apophatic theology has remained important. This book is an investigation of the significance of this perspective. It presents the tradition of negative theology from Plato to the Reformation, focussing particularly on Maximus Confessor, Nicholas Cusanus and Martin Luther as Christologically informed thinkers who develop an apophatic theology that still seems to contain a potential for renewal both from an ecumenical and a philosophical perspective. The relevance of this perspective is then explored through a discussion of the continuity between these thinkers and some contemporary contributions both from a Western and non-Western context.