This review traces the history and development of organic photoconductors (OPCs), the multilayer thin film photosensitive element in electrophotographic printers, from Chester Carlson’s 1938 demonstration of xerography to the present. A brief discussion of the history of electrophotography is followed by a review of OPC basics and the development of specific charge generating materials (CGMs) and charge transporting materials (CTMs). Next is a discussion of OPC commercialization and the last section demonstrates the cycle of OPC research and development by the number of OPC presentations at international conferences.