Today, ultrasonic signal is being used for predicting material behavior, characterizing (detecting internal anomalies in) a variety of engineering structures, as well as for inspecting human body parts like - tumors, bones, and unborn fetuses. Because of the ever-increasing popularity of the ultrasonic techniques in a wide range of applications, this technology has received a lot of attention from the research community. This book presents some new developments in ultrasonic research for material characterization and nondestructive evaluation (NDE) of materials. Application areas cover both engineering and biological materials.