Vittorio Mathieu investigates Kant's reflections in the opus postumum against the background of critical transcendental philosophy. On the one hand, he identifies the problems in Kant's earlier writings that might have motivated his later reflections, taking his point of departure from the Critique of Judgment being particularly impressive. Second, Mathieu traces various topics treated by Kant (ether-deduction, self-affection, existence, organism, unity of philosophy) and offers an interpretation of the relevant passages in the opus postumum. Mathieu's book remains one of the most important on Kant's posthumous work. It is still widely cited today and rightfully so. There is hardly a treatise on Kant's late work that fails to deliver its take on Mathieu. Dina Emundts