The Christian concept of 'God' names a category with surprisingly heterogeneous contents. In the Old Testament traditions God is an anthropomorphic agent; in Christian theology God often appears as a personalized metaphysical principle; philosophers of religion try to find the inherent rationality of this concept; finally, some natural scientists regard God as the "intelligent designer" of the world. What is common to all these ideas, covering a time span of about 2,500 years, is that representations of God are triggered by the perception of order and control in the world.