Bridging the gap between theory and practice, it clarifies important phenomena in photorefractive media and shows how to apply these phenomena in actual situations. While the focus is on the theory of propagation of optical waves and the mixing of electromagnetic radiation in these media, there are also many numerical examples based on real-world situations included for hands-on guidance. In addition to exploring the basics of electromagnetic waves and periodic structures, this practical guide discusses optical phase conjugators and photorefractive resonators; covers fundamental properties of gratings and holograms; details how to use optical information processing, optical interconnection and neural networks; and treats high-order photorefractive effects in optical fibers.