Critik der practischen Vernunft.

Two first editions in a contemporary German binding

First editions of Kant's Critique of Practical Reason and On a Discovery in a pleasing contemporary binding. The former work established Kant's moral thinking as a cardinal reference in the successive development of ethics; the latter, comparatively little-known, is Kant's defence of his own philosophy against attacks made by Johann Augustus Eberhard.

In The Critique of Practical Reason, the second of his critical works, Kant develops the concept of categorical imperative. "The influence of Kant is paramount in the critical method of modern philosophy. No other thinker has been able to hold with such firmness the balance between speculative and empirical ideas. His penetrating analysis of the elements involved in synthesis, and the subjective process by which these elements are realized in the individual consciousness, demonstrated the operation of 'pure reason'; and the simplicity and cogency of his arguments achieved immediate fame" (PMM).

Eberhard, a leading Wolffian, joined with other critics of Kant to found the Philosophisches Magazin, the main goal of which was to challenge Kant's philosophy. The Magazin published many articles attacking Kant's ideas, leading to a long debate between Kant, Eberhard and their respective allies. Ultimately, Kant and his followers won the dispute, with his ideas retaining their ascendancy in German philosophy, which they would hold for decades.