On the Principle of Sufficient Reason

This little known work by the German pessimist and critic of Hegel was originally written as a doctoral dissertation when Schopenhauer was just 26. But it was later revised when the philosopher was 60. So important did he consider this work that he often underscored the fact that no one could hope to understand his magnum opus, The World as Will and Representation without first having read this work. Schopenhauer takes up where Kant left off in response to Hume, and his insights into the nature of perception and understanding remain amazingly relevant and still unsurpassed.