This paper briefly reviews the field of Bragg-diffraction imaging starting with the history of the investigation of light-sound interaction which led up to the development of the Bragg-diffraction imaging systems. The operation of two different systems are described along with a discussion of their advantages and disadvantages. A rigorous analysis of the imaging principles is presented. The analysis uses a quantum-mechanical approach to illustrate the basic Bragg condition and frequency shift; wave theory based on Maxwell's equations to describe the three-dimensional light-sound interaction; and, ray theory, based on the Eikonal equations, to determine the actual position of the Bragg images and the aberrations present in the imaging process. The application of Bragg-diffraction imaging to medical diagnosis and nondestructive testing is discussed.