

A minority remained in the spaceships, avoiding overpopulation through strict birth control, preserving the advanced technology of Earth and trading this knowledge with the colonists in exchange for essential raw materials. Some of them settled on planets, where they struggled hard to make them habitable and to produce enough food to survive, leaving too little time for education and leisure.

The survivors scattered through the galaxy in hastily built multigenerational spaceships. The setting: Earth has been completely destroyed in a global conflagration in the 21st century. I have read literally hundreds of coming of age stories, most of them fantasy or SF, which might explain my lower rating for what is arguably one of the least conventional and better written of the lot. , Jo Walton argues that the author's goal was more subversive than paying homage to the grandmaster of science-fiction, a point sustained by the known critical disagreement between the two. In her excellent review of the Panshin novel Somebody quiped this is the best juvenile that Heinlein never wrote.
