Updated, revised, and restructured to reflect the latest advances in science and applications, the fourth edition of this best-selling industry and research reference covers the fundamental physical acoustics of ultrasonics and transducers, with a focus on piezoelectric and magnetostrictive modalities. It then discusses the full breadth of ultrasonics applications involving low power (sensing) and high power (processing) for research, industrial, and medical use. This book includes new content covering computer modeling used for acoustic and elastic wave phenomena, including scattering, mode conversion, transmission through layered media, Rayleigh and Lamb waves and flexural plates, modern horn design tools, Langevin transducers, and material characterization. There is more attention on process monitoring and advanced nondestructive testing and evaluation (NDT/NDE), including phased array ultrasound (PAUT), long-range inspection, using guided ultrasonic waves (GUW), internally rotary inspection systems (IRIS), time-of-flight diffraction (TOFD), and acoustic emission (AE). These methods are discussed and applied to both metals and nonmetals using illustrations in various industries, including now additionally for food and beverage products. The topics of defect sizing, capabilities, and limitations, including the probability of detection (POD), are introduced. Three chapters provide a new treatment of high-power ultrasonics, for both fluids and solids, and again, with examples of industrial engineering, food and beverage, pharmaceuticals, petrochemicals, and other process applications. Expanded coverage is given to medical and biological applications, covering diagnostics, therapy, and, at the highest powers, surgery. Key Features Provides an overview of fundamental analysis and transducer technologies needed to design and develop both measurement and processing systems Considers applications in material characterization and metrology Covers ultrasonic nondestructive testing and evaluation and high-power ultrasonics, which involves interactions that change the state of material Highlights medical and biomedical applications of ultrasound, focusing on the physical acoustics and the technology employed for diagnosis, therapy, surgery, and research This book is intended for both the undergraduate and graduate scientists and engineers, as well as the working professional, who seeks to understand the fundamentals together with a holistic treatment of the field of ultrasonics and its diversity of applications.