Due care has been taken to provide correct chemical structures of various plant constituents based on the Natural Products according to the latest Merck Index so that the end-users and teachers may find it authentic. Appropriate explanations of various courses of sunthctic routes have been explored to render the text matter easily comprehensible as well as convincing. Both M.Sc. Students specializing in Chemistry Biotechnology Biochemistry Pharmaceutical Chemistry Molecular Biology Microbiology and other allied disciplines may find the present textbook a pathfinder.