Orphans of the Sky

While it is published as a single volume, the work is a compilation of two separate novellas, Universe and Common Sense, which were originally published in 1941. These stories are also categorized as part of the author's broader Future History series.

The concept of a generation ship where the inhabitants have forgotten their true purpose and origin has been highly influential in the genre. It is frequently cited as a foundational example of the trope, with themes and plot elements that have been echoed in various television episodes and later novels.