In his controversial work, Kant and the Problem of Metaphysics (1929), Martin Heidegger claimed that the Kantian theory of imagination represents a watershed in Western philosophy. Heidegger analyses here how in attempting to lay the foundations for a new scientific metaphysics, Kant hit upon the discovery that all our knowledge of being derives from the ‘finitude of human subjectivity’.1 This ‘finitude’ was necessarily demonstrated by the fact that pure reason could not reach the objects of experience except through the sensible intuition of time and space: that is, through the finite limits laid down by imagination. Whereas many orthodox interpreters chose to read this as confirmation of the traditional ‘mediational’ role of imagination, Heidegger insisted that Kant had radically redefined imagination as the ‘formative centre’ of both intuition and thought. To vindicate his conviction, Heidegger conducts a lengthy exploration of the Kantian treatment of the transcendental imagination in the first edition of the Critique of Pure Reason.