The collection consists of papers and images compiled by Jack C. Riley. The majority of materials relate to Electro Scientific Industries (ESI), where Riley worked from the 1950s to the 2000s. These materials include engineering bulletins, instruction manuals, technical articles, slides for presentations, and photographs and negatives of ESI facilities and equipment. Additional materials include papers relating to Riley’s work at the Radio Research Laboratory in Cambridge, Massachusetts; his work on beam interference, which was also done in Cambridge; published papers by Riley and other electrical engineers; and issues of the publication General Radio Experimenter.