The book entitled "Naturally occurring alkaloids and iridoids: Chemistry and biological importance" contains the overview about the bio-active alkaloids and iridoids. Since, these class of natural products having significant medicinal values, so the complete chemistry including biosynthesis and the structure elucidation on the basis of advanced NMR techniques has been discussed in brief. The isolation techniques for these constituents are being highly emphasized. Their role in the plants and animals and detailed classification are also included in the text. This is a reference book which contains more than 300 references. The book is a summary of various significant researches and other contributions in the form of reviews and books, and the source of the facts discussed in the book are being cited in the text. The matter of this book would be helpful for postgraduate students as well as researcher working in the field of natural products chemistry.