The writings of German philosopher ARTHUR SCHOPENHAUER (1788-1860) were a profound influence on art and aesthetics, music and literature in the 19th century. Among his many writings are *On the Fourfold Root of the Principle of Sufficient Reason* (1847) and *The World as Will and Idea* (1819), considered his masterpiece.

General editor's preface; Editorial notes and references; Introduction; Notes on text and translation; Chronology; Bibliography; Part I. On the Fourfold Root of the Principle of Sufficient Reason: 1. Introduction; 2. Survey of what is most important in previous teachings about the principle of sufficient reason; 3. Inadequacy of previous accounts and sketch of a new one; 4. On the first class of objects for the subject and the form of the principle of sufficient reason governing in it; 5. On the second class of objects for the subject and the form of the principle of sufficient reason governing in it; 6. On the third class of objects for the subject and the form of the principle of sufficient reason governing in it; 7. On the fourth class of objects for the subject and the form of the principle of sufficient reason governing in it; 8. General remarks and results; Variants in different editions; Collation of the two editions; Part II. On Vision and Colours: 9. On vision; 10. On colours; Variants in different editions; Part III. On Will in Nature: 11. Introduction; 12. Physiology and pathology; 13. Comparative anatomy; 14. Plant physiology; 15. Physical astronomy; 16. Linguistics; 17. Animal magnetism and magic; 18. Sinology; Reference to ethics; Conclusion; Variants in different editions; Glossary of names; Index.