The Chemistry of the Limonoids from Meliaceae.- I. Introduction.- II. Classes of Limonoids.- III. Outlook for Future Work.- IV. Tables.- References.- Recent Progress in the Chemistry of Liehen Substances.- 1. Introduction.- 2. Carbohydrates.- 3. Amino-acid Derivatives.- 4. 4-Ylidenetetronic Acids.- 5. Aliphatic Acids and Related Compounds.- 6. Mononuclear Phenolic Compounds from Lichens.- 7. Chromones.- 8. Xanthones.- 9. Anthraquinones arid Biogenetically Related Compounds.- 10. Depsides.- 11. Depsidones and Related Diphenyl Ethers.- 12. Dibenzofurans and Biogenetically Related Compounds.- 13. Mevalonic Acid Derivatives.- 14. Liehen Chemotaxonomy.- References.- Paralytic Shellfish Poisons.- I. Introduction.- II. Occurrence and Isolation.- III. Structure and Chemistry.- IV. Synthesis.- V. Biosynthesis.- VI. Pharmacology.- References.- Aiithor Index.