This straightforward text provides a concise yet comprehensive introduction to the chemistry involved in the biosynthesis of natural products. It explains the connections between the primary and secondary metabolites, outlines the chemistry mediated by the major enzyme cofactors, and describes the methods for the elucidation of biosynthetic pathways. The different classes of metabolites are then discussed, with an emphasis on the pharmacological and toxicological significance of the various compounds. The ecological significance of a wide variety of natural compounds is also examined. This book is intended for undergraduate chemists, pharmacologists, and pharmacists on lecture courses in natural products/biosynthesis (core 3rd year course).