In the future, Malthusian overpopulation on Earth has been averted by the invention of teleportation, called the "Ramsbotham jump", which sends the excess population to colonize other planets.

Rod, acting on his older sister's advice, takes hunting knives and basic survival gear, but no high-tech weaponry, on the grounds that the latter could make him overconfident.

Rod has no taste for politics or administration and is happy to have Grant Cowper, an older college student and born politician, elected as mayor.

Heinlein tracks the social development of the frontier community of educated young Westerners deprived of technology, followed by their society's abrupt dissolution when Earth reestablishes contact.

All of the students go back to Earth willingly enough except for Rod, who has great difficulty reverting from the status of head of a small but sovereign state to a teenager whom the adult rescuers casually brush aside.

As in Lord of the Flies, which had been published a year earlier, isolation reveals the true natures of the students as individuals, but it also demonstrates some of the constants of human existence as a social animal.

Its underlying themes run counter to those in Lord of the Flies, however, in that it shows a belief in the inherent strength of humans as proto-adults who can self-organize rather than descend into barbarism.

Some of the students fall victim to their own foolishness, and others turn out to be thugs, but that is a part of human nature, just as the counter-trends take the group as a whole towards the beginnings of a stable society.

In both its romanticization of the pioneer and its glorification of Homo sapiens as the toughest player in the Darwinian game, it presages themes developed further in books like Time Enough for Love and Starship Troopers.