The “supernatural,” as that term is traditionally used in theology, is that which is beyond the power of the natural order to produce on its own. Hence it can be produced only by what has causal power superior to that of anything in the natural order, namely the divine cause of the natural order. Insofar as the natural order depends on this supernatural cause, the supernatural is metaphysically prior to the natural. However, the natural is epistemologically prior to the supernatural, insofar as we cannot form a conception of the supernatural except by contrast with the natural and cannot know whether there is such a thing as the supernatural unless we can reason to its existence from the existence of the natural order. A proper understanding of the supernatural thus presupposes a proper understanding of the natural order and of the causal relation between that order and its cause. This chapter offers an account of these matters and of their implications for theological issues concerning causal arguments for God’s existence, divine conservation and concurrence, miracles, nature and grace, faith and reason, and the notion of a theological mystery (viz. what is beyond the power of the intellect to discover on its own).