Ultrasonics has made a major impact in many areas, including medical diagnosis and industrial nondestructive testing. As a results of some pioneering work in the 1960s and early 1970s, followed by more systematic studies in the late 1970s and 1980s, laser techniques have now been established as a viable non-contact alternative to piezo-electric transducers for generating and receiving ultrasound. Substantial research has quantified the interactions between the optical and ultrasonic fields, and various potential applications have been demonstrated, mostly under laboratory conditions. The purpose of this book is to review the principles underlying both generation and reception processes in preparation for a discussion of likely applications. Thus the first chapter will briefly introduce the two main subjects of this book: ultrasonics and lasers. Techniques based on the diffraction of light are discussed in chapter 2. While the main thrust of the book is towards the use of lasers for ultrasonic measurement, there are some important uses of ultrasonic devices in laser optics and a brief review of these is included. Chapter 3 explores various types of laser interferometry in depth, before considering applications of interferometry to ultrasonics in chapter 4. Chapter 5 takes the form of a comprehensive study of the generation by laser of ultrasonic waves, whilst chapter 6 reviews a very wide range of applications for laser-generated ultrasound. This book on laser techniques in ultrasonics is written for as broad a readership as possible, including both researchers and industrialists alike.