Anderson listed "Entity" as part of the Psychotechnic League series in a timeline published in the Winter 1955 issue of Startling Stories, but it was not included in a later timeline that appeared in the Psychotechnic League collection Starship (1982). Although one character in "Entity" mentions that the discovery of hyperdrive occurred "a few decades" earlier, the Startling timeline has the story take place in 3150, nearly four centuries after the discovery of hyperdrive in the Psychotechnic League universe. The late date may have been Anderson's way of explaining away the absence of the sphere's power broadcasting technology in any of the other Psychotechnic League stories. There is nothing in "Entity" that conflicts with the rest of the Psychotechnic series, but neither is there any positive correlation with it. External links Anderson and Gergen are mentioned in a brief history of the Minneapolis Fantasy Society. See also Sphere, a later film about a similar sphere 2001: A Space Odyssey, a later novel and film featuring a black monolith (object) The Sentinel, a previous short story that lead to 2001: A Space Odyssey External links 1949 short stories Short stories by Poul Anderson Works originally published in Analog Science Fiction and Fact