This book focuses on optical and acoustic methods for experimental dynamics. Light and sound are complementary in many respects. The frequency ranges are completely different in most applications; sound can pass through most solid materials and light can travel in vacuum. It is important to consider the application of both methods, including simultaneous application. This is the first book that covers both optical and acoustic techniques applied to experimental mechanics. Utilization of both techniques is advantageous for various applications because the optical and acoustic waves are complementary to each other. This book explains the science underlying the optical and acoustic techniques.