As both an informational molecule and a catalyst, RNA may hold clues to the emergence of genetic self-replication and the origins of life. The first, 1993 edition of this important work was acclaimed as unique and authoritative. The new edition has been revised, updated, and extended, and offers a completely current perspective on the modern world of RNA and the light it sheds on a prebiotic era perhaps dominated by this extraordinarily versatile molecule. This book is essential reading for everyone interested in the biology of nucleic acids, and is a valuable resource for teaching as well as investigative science.