Fundamental measurement problems in engineering, mechanics, manufacturing, and physics are now being solved by powerful optical methods. This book presents a lucid, up-to-date discussion of these optical methods. Beginning from a firm base in modern optics, the book proceeds through relevant theory of interference and diffraction and integrates this theory with descriptions of laboratory techniques and apparatus. Among the techniques discussed are classical interferometry, photoelasticity, geometric moire, spatial filtering, moire interferometry, holography, holographic interferometry, laser speckle interferometry, and video-based speckle methods. By providing a firm base in the physical principles and at the same time allowing the reader to perform meaningful experiments related to the topic being studied, the book offers a unique user-oriented approach that will appeal to students, researchers and practising engineers.