This 1748 treatise by David Hume offers an accessible account of his unprecedented and challenging notions about the limitations of the human mind. It expounds the most influential theory of causality in modern times -- one that prompted Kant to create an entirely new school of thought. Highly controversial in the 18th century, this work remains provocative in its discussions of the appeal of skepticism, the logical coexistence of free will and determinism, and the deficiencies of religious doctrine.