"Preface to the Second Edition Almost exactly ten years have passed since the submission of the manuscript for the first edition of Fundamentals and Applications of Ultrasonic Waves and it is only human to think back on that occasion. At that time I was director of an ultrasonics research group and very much in the "thick of things" regarding external relations and international collaborations, including active participation in the IEEE ultrasonics symposia. There were a lot of advantages: interesting colleagues to converse with, daily access to new results, both from my research group and from the current literature, continual feedback from external groups, and so on. All of this kept me fully abreast of the latest detailed developments in research areas of personal interest in ultrasonics, together with general input on what was going on in related areas. Following that period, I retired from university research to become fully involved in a spinoff company, Microbridge Technologies Inc., which had I co-founded and whose vocation was in developing microelectronic components for sensing devices. This experience gave me access to an industrial viewpoint of MEMS devices and sensor applications, as well as a different perception of the meaning of the word "urgent." Today the situation is very different. Following my retirement from Microbridge I have been leading a rural lifestyle far removed from both university research and industrial microelectronics. The detailed contacts are gone, but occasional discussions with ex-colleagues, and the time to reflect on more general things have provided something else, which can be described as a clearer view of the big picture"-- Provided by publisher.