Natural Products Chemistry continues to grow at an increasing pace and this growth is reflected in the present volume of Studies in Natural Products Chemistry, which is the 20th of this series. The first 20 volumes were largely devoted to structure and synthesis of various classes of natural products, irrespective of their bioactivity. Subsequent volumes of this series will however be devoted to the chemistry of bioactive natural products and will therefore a departure from the earlier volumes. The present volume contains contributions from a number of eminent scientists and covers interesting reviews on terpenes, alkaloids and other types of natural products reported from terrestrial and marine sources. Comprehensive indexes covering all the 20 volumes have been prepared which include a Cumulative General Subject Index along with more focused Cumulative Indices on Organic Synthesis, Pharmacological Activity and Biological Source. This comprehensive indexing of the volumes should make the entire series much more valuable and user-friendly.