7 Donnelly, R. J., Herman, R., and Prigogine, I., Nonequilibrium Thermodynamics, Variational Techniques and Stability, 1st ed., University of Chicago Press, Chicago, 1966. 8 Silver, R. S., An Introduction to Thermodynamics, 1st ed., Cambridge University Press, Cambridge, 1971, pp. 47–52. 9 El-Sayed, Y. M., "On the Generalization of Thermodynamics," unpublished report, Department of Mechanical Engineering, Glasgow University, 1971. 10 Schlögl, F., "Produced Entropy in Quantum Statistics," Zeitschrift für Physik, Vol. 249, 1971, pp. 1–11. "Diffraction of Elastic Waves and Dynamic Stress Concentrations. By Y.-H. Pao and C.-C. Mow. Crane, Russak & Co. Inc., New York, 1973. 693 Pages." Reviewed by J. D. Achenbach. This book provides a comprehensive collection of analytical methods and numerical data for elastodynamic diffraction problems. It includes a history of elastic wave diffraction studies, summaries of elasticity theory, and detailed discussions on wave propagation in elastic solids. The book covers various diffraction problems, including those involving cylindrical and spherical obstacles, and includes analysis of stress singularities at the edge of a semi-infinite crack. It is a valuable resource for those interested in elastodynamic effects. "Materials Science. By A. L. Ruoff. Prentice-Hall, Englewood Cliffs, N. J. 1973. vii-928. $18.95 Cloth." Reviewed by A. Phillips. This is an excellent introductory book on material science, covering a wide range of topics such as material properties, microstructure, chemical equilibria, and mechanical, electrical, optical, and magnetic properties. It is well-written, includes numerous examples and problems, and is suitable for undergraduate teaching.7 Donnelly, R. J., Herman, R., and Prigogine, I., Nonequilibrium Thermodynamics, Variational Techniques and Stability, 1st ed., University of Chicago Press, Chicago, 1966. 8 Silver, R. S., An Introduction to Thermodynamics, 1st ed., Cambridge University Press, Cambridge, 1971, pp. 47–52. 9 El-Sayed, Y. M., "On the Generalization of Thermodynamics," unpublished report, Department of Mechanical Engineering, Glasgow University, 1971. 10 Schlögl, F., "Produced Entropy in Quantum Statistics," Zeitschrift für Physik, Vol. 249, 1971, pp. 1–11. "Diffraction of Elastic Waves and Dynamic Stress Concentrations. By Y.-H. Pao and C.-C. Mow. Crane, Russak & Co. Inc., New York, 1973. 693 Pages." Reviewed by J. D. Achenbach. This book provides a comprehensive collection of analytical methods and numerical data for elastodynamic diffraction problems. It includes a history of elastic wave diffraction studies, summaries of elasticity theory, and detailed discussions on wave propagation in elastic solids. The book covers various diffraction problems, including those involving cylindrical and spherical obstacles, and includes analysis of stress singularities at the edge of a semi-infinite crack. It is a valuable resource for those interested in elastodynamic effects. "Materials Science. By A. L. Ruoff. Prentice-Hall, Englewood Cliffs, N. J. 1973. vii-928. $18.95 Cloth." Reviewed by A. Phillips. This is an excellent introductory book on material science, covering a wide range of topics such as material properties, microstructure, chemical equilibria, and mechanical, electrical, optical, and magnetic properties. It is well-written, includes numerous examples and problems, and is suitable for undergraduate teaching.