A Structural Parallel

Robert Heinlein's Future History is two collections, two novels and a shorter volume that is an appendix to the main action. However, because two further short stories are set between the two novels, Volume III of the Future History has always comprised the first novel and these two stories under the title, Revolt In 2100. The novel describes the Second American Revolution whereas the stories describe two aspects of post-Revolutionary society.

Similarly, in Poul Anderson's Technic History, two stories, "A Little Knowledge" and "Lodestar," are set between the novels, Satan's World and Mirkheim, and might have been collected in the same volume as Satan's World if the series had ever been published in consecutive order before it was brought together in the seven omnibus volumes of Baen Books' The Technic Civilization Saga. Satan's World describes an external threat to Technic civilization. The two short stories show growing internal problems before the beginning of the end of the Polesotechnic League happens in Mirkheim.