This book by Yeo V. Stupochenko, S. A. Losev and A. I. Osipov distin- guishes itself as an unusually comprehensive treatment of both the the- oretical and experimental aspects of the subject of relaxation processes in shock waves. S. A. Losev has done a considerable amount of work in molec- ular absorption spectroscopy of gases in relaxation, and, consequently, the chapter on experimental methods of study of nonequilibrium phenomena in shock waves has turned out to be particularly extensive in both scope and depth. A. I. Osipov has contributed extensively to the theoretical understanding of relaxation processes in gases through his work on transi- tion probability in nonadiabatic collisions by quantum-mechanical calcula- tion as can be seen from the many quotations in the chapter on relaxation processes in shock waves. Finally, Yeo V. Stupochenko's heavy contribution to the development of the study of nonequilibrium gas flow must also be mentioned, as it is obviously reflected at various places throughout the book. It is worth particular mention that the authors have compiled the most extensive bibliography of references (over six hundred in total) in the litera- ture of relaxation gasdynamics to date. The authors' thorough familiarity with the Western (particularly American) work in this ,!rea can be seen from the many Western reference"~quoted, about two-thirds of the total number. On the contrary, most of the more than two hundred Russian references are not popularly known in the West and, therefore, should be of value to the English-speaking readers.