This book is a self-contained introduction to the theory of atomic motion in proteins and nucleic acids. An understanding of such motion is essential because it plays a crucially important role in biological activity. The authors, both of whom are well known for their work in this field, describe in detail the major theoretical methods that are likely to be useful in the computer-aided design of drugs, enzymes and other molecules. A variety of theoretical and experimental studies is described and these are critically analyzed to provide a comprehensive picture of dynamic aspects of biomolecular structure and function. The book will be of interest to graduate students and research workers in structural biochemistry (X-ray diffraction and NMR), theoretical chemistry (liquids and polymers), biophysics, enzymology, molecular biology, pharmaceutical chemistry, genetic engineering and biotechnology.