The philosophical literature on Kant's attitude towards metaphysics deals mainly with two of its aspects: (a) the traces of traditional metaphysics to be found in Kant's critical system, either in spite of his own criticism or as the background of this very criticism; (b) the interpretation of Kant's criticism itself as a metaphysical system, either disguised or avowed, on its own merits. The first approach is to be found in the various attempts to throw historical light on Kant's mature critical system, as for instance by Paulsen and Heimsoeth. The second approach is found, e.g., in Heidegger's book on Kant and Metaphysics (see on this the Appendix to the present book).