It has been more than a decade since SPIE Press published the first book on shearography in 2003: Digital Shearography: Theory and Application of Digital Speckle Pattern Shearing Interferometry by Wolfgang Steinchen and Lianxiang Yang. That book has greatly contributed to enabling better understanding and improvement of the digital shearography technique. During the past 13 years, digital shearography has been widely applied by industry and accepted as a practical tool for nondestructive testing; at the same time, the technique itself has been greatly improved. This new book presents the principles and applications of phase shift digital shearography, especially spatial phase shift digital shearography, and reviews the state-of-the-art improvements and new developments of digital shearography for nondestructive testing and strain measurement. The authors provide a unified, self-contained treatment of the theory, practice, and applications of shearographic interferometry with problems and questions. The book will meet the requirements of graduate students, as well as be of assistance in research and industry applications.