The aim of this book is to give a comprehensive description of the basic methods used in the ultraviolet spectroscopy of proteins, to discuss new trends and development of these methods, and to analyze their different applications in the study of various aspects of protein structure and dynamics. Ultraviolet spectroscopy is one of the oldest and most popular methods in the field of biochemistry and molecular biophysics. At present, it is difficult to imagine the biochemical laboratory without a recording spectrophotometer or spectrofluorimeter. There are several hundreds of publications directly devoted to protein ultraviolet spectroscopy and in a great number of studies UV spectroscopic methods are used for the structural analysis of different proteins. Meanwhile a unified description of the theoretical basis of the methods, experimental techniques, data analysis, and generalization of results obtained in solving the specific problems of protein structure are lacking. There are three reasons for which a monograph on ultraviolet spectroscopy is needed today. Firstly, there has been significant growth in facilities of experimental technique, its precision, and versatility associated with computer data analysts. This new technique is available to a wide circle of scientists engaged in the field of protein research. Most of them are not spectroscopists and, thus, there is a need for a conceivable and precise source of information on how to use this method and what kind of data it should provide.