The problem alluded to in the title of this essay is one that has plagued Kant exegesis since the appearance of the first Critique. As we shall see, an attempt to come to grips with this problem involves a fresh presentation of the over-all structure of Kant's philosophical approach, of Kant's basic imagery; involving in particular a novel appraisal of the significance of two concepts that lie at the core of the Critique Pure Reason, and which have always been felt to stand in need of further explication: the concept of the thing-in-itself and that of the transcendental object.