Based on lectures by the author, this volume is designed as a textbook on general ultrasonics. The text provides coverage of the propagation of ultrasonic waves in media with different elastic properties and under conditions close to those encountered in scientific and practical applications of ultrasound. As well as classical material and data from original sources, the book includes experimental data on the velocity of sound in isotropic solids and crystals. Each chapter is complemented by problems and their solutions.