This proposed book is an attempt to place theology and philosophy in an entirely new sort of relationship. Instead of regarding philosophy as a prolegomenon to theology, I suggest that the enterprises should rather run in interlinked parallel and that if a philosophical critique of theology is possible, then so is the reverse. This is what this book seeks to carry out. It builds upon the new historiography of philosophy in recent years which shows that the turn to a recognisable ‘modern’ philosophy occurred around the year 1300 and not with Kant. One implication of this is that this turn was itself highly theological and therefore that modern philosophy is grounded in a certain kind of theology. If that theology can be called into question on theological grounds, then so, also, in certain respects, can almost the entirety of modern philosophy in its dominant currents. The book also builds upon a related new non-Kantian return to metaphysics in early 21st century philosophy, which often takes the form of a quest for a pure immanence. While upholding the return to metaphysics I criticise this quest, and reveal its inherent problems, especially the way it tends to re-engender virulent forms of dualism. Instead I contend that, perhaps surprisingly, only philosophies of transcendence linked with a Christian theology can overcome these dualities and in particular sustain a mediating balance between ‘life’ and ‘truth’.