In 1781, Immanuel Kant published his first and most famous work, the "Critique of Pure Reason." To the German philosopher's dismay, the work was at first poorly received and largely misunderstood by his readers. As a result, two years later Kant produced his "Prolegomena to any Future Metaphysics that will be Able to Present Itself as a Science" to serve as an introduction to the "Critique." He restated the main ideas of his philosophy in what Schopenhauer, in 1819, declared was "the finest and most comprehensible of Kant's principal works, which is far too little read, for it immensely facilitates the study of his philosophy