Sequencing, cloning, transcription - these are but a few key techniques behind the current breathtaking advances in molecular biology and biochemistry. As these methods continuosly diversify, biochemists need a sound chemical understanding to keep the pace. Chemists beginning working in the molecular biology lab need an introduction to this field from their point of view. This book serves both: it describes most of the known chemical reactions of nucleosides, nucleotides, and nucleic acids in sufficient detail to provide the desired background, and additionally, the fundamental relations between sequence, structure and functionality of nucleic acids are presented. The first edition of this book, which was published in Russian, has immediately become a recognized standard reference. This second, thoroughly revised and updated edition, now published in English, is likely to achieve a similar position in the international scientific community.