This book provides a review of state-of-the-art technological developments in applied ultrasonics with a focus on recent advances in ultrasonic research, covering metrological applications, non-destructive evaluation, sensing, devices, and physics, as well as medical diagnosis and treatment. The first part of this book focuses on the physics of acoustic waves, and their propagation and addresses viscoelasticity, as well as metrological applications including laser ultrasonics. Part two reviews some recent developments of importance to industrial applications, while the final part introduces developments in biomedical applications. The book will be an essential resource and instructional guide to the field for a broad range of students, researchers, and engineers. The reader can readily understand the direction of research in the subject, appreciate the numerous possibilities of using ultrasound, and grasp the potential applications of the phenomenon and current challenges. The book includes chapters from authors with expertise in different areas of ultrasonics and its application.