The book comprehensively studied the range of issues related to the phenomenon of photorefraction. Modern data on the physical basis of this phenomenon are presented and analyzed, the use of photorefractive media for recording, storing and processing information is considered in detail. In addition to chapters devoted to special issues, the monograph also contains introductory sections on the basics of holography, optical information processing and photorefractive effect physics, as well as a reference chapter on photorefractive crystals.