The transcendental dialectic, which is thedestructive partof the Critique of Pure Reason thatcritizises traditional metaphysics, is typically treated in systematic perspective as a corollary to the doctrinaire parts. The study undertaken in this book focuses on the systematic conception of the dialectic: the teaching that reason’s reference to the unconditioned is a necessary illusion. The book argues that the dialectic isthe foundation of critical philosophy and that its negative and positive teachings concerning reason are inextricably interlinked.