There has been a recent upsurge in attention to the categories of freedom in Kant’s “Critique of Practical Reason.” Puls has deepened the discussion with a study that takes the perspective of developmental history. He engages in a comprehensive analysis of the architectonic position of practical categories of reason in Kant. The implication of these practical categories for Kant’s overall critique of reason are examined, from the early Reflections to the Metaphysics of Morals.