Note: Irving Heine is known only for the 1955 story. Reginald1 (1979) states this is a pseudonym for an unidentified author. The Encyclopedia of Science Fiction attributed the work to Denis Hughes until June 2022: "Irving Heine, author of a single title, was formerly thought to be a Hughes pseudonym but this seems not to be the case." --SFE4, "Hughes, Denis", entry updated 2022-06-13 (quoted text new since 2022-01-05)