The following chapters deal with questions concerning the being and nature of God, and God's relation to empirical reality. People often talk past each other when they debate about God. In the worst cases, atheists deny the existence of a God which no theist ever claimed to exist. In order to avoid confusions like this we need to be clear about the function of the term "God" in its different contexts of use. In what follows, I distinguish between the functions of "God" in philosophical contexts on the one hand, and in theological contexts on the other in order to facilitate an analysis of the ground of empirical reality from a purely philosophical point of view.