When most of us hear the word ultrasound, we typically think of diagnostic imaging; especially in regard to its use in obstetrics. Ultrasound, however, can also be used for a wide variety of therapeutic applications, which the author has chosen as the theme of this book. The book begins with a primer on sound waves, which are followed with some basics on imaging. Next are descriptions of the evolving technology, with a specific emphasis on medical applications. Examples are given of the different procedures that are carried out using sophisticated, non-invasive, image-guided devices. Each procedure is carefully explained with the help of many detailed illustrations. Examples of these include the destruction of tumors deep within the body using highly focused ultrasound beams. Especially impressive are the treatments that are guided with realtime MRI. One in particular is employed for opening barriers in the brain to facilitate the delivery of a range of agents for treating conditions such as Alzheimer’s disease. For almost thirty years, Victor Frenkel has worked as a teacher, mentor, and research scientist at medical schools, engineering departments, and government institutions. Along the way he made his own contributions in the field of therapeutic ultrasound. These include the development of novel treatment protocols, and also designing and building the devices used to carry them out. Told with easy-to-follow language, including key historical and cultural perspectives, this book is meant for anyone who loves cutting edge technology, especially pertaining to medical treatments.