Tunnel in the Sky

The novel is set in the future, when Malthusian overpopulation on Earth has been averted by the invention of teleportation, called the "Ramsbotham jump," which is used to send Earth's excess population to colonize other planets. However, the costs of operating the device mean that the colonies are isolated from Earth until they can produce something to justify two-way trade. Because modern technology requires a supporting infrastructure, the colonists employ technology from the frontier era (such as horses instead of tractors).

Rod Walker is a high school student who dreams of becoming a professional colonist. The final test of his Advanced Survival class is to stay alive on an unfamiliar planet for between two and ten days. Students may team up and equip themselves with whatever gear they can carry, but they are otherwise completely on their own. They are told only that the challenges are neither insurmountable nor unreasonable. On test day, students walk through the Ramsbotham portal and find themselves alone on a strange planet, but reasonably close to the pickup point. Rod, acting on his older sister's advice, takes hunting knives and basic survival gear, rather than high-tech weaponry, on the grounds that the latter could make him overconfident. The last advice that the students receive is to "watch out for stobor."

On the second day, Rod is ambushed and knocked unconscious by a thief. When he wakes up, all that he has left is a spare knife hidden under a bandage. In his desperate concentration on survival, he loses track of time. Eventually, he teams up with Jacqueline "Jack" Daudet, a student from another class whom he initially mistakes for a male. When she tells him that more than ten days have elapsed without contact, he realizes that something has gone wrong with the portal that was supposed to recover them and that they are stranded.

They start recruiting others to build a settlement for long term survival and Rod becomes the de facto leader of a community that eventually grows to around 75 people. Disagreements reveal the need to elect a government for the new town. Rod has no taste for politics or administration and is happy to have Grant Cowper, an older college student and born politician, elected mayor. Grant proves to be much better at talking than at getting things done. Despite disagreeing with many of Grant's policies, Rod supports him. Grant ignores Rod's warning that they are living in a dangerously hard-to-defend location and that they should move to a cave system that he has found. When a species that had been thought to be harmless suddenly changes its behavior and stampedes through their camp, the settlement is devastated and Grant is killed. Rod is put back in charge.

Heinlein tracks the social development of the frontier community of educated Westerners deprived of technology, followed by its abrupt dissolution when contact with Earth is reestablished. After nearly two years of isolation, the culture shock experienced by the survivors highlights for them and the reader the pain and uncertainty of becoming an adult by reversing the process abruptly. Each of the students returns from being a self-responsible member of an autonomous community to being regarded as a youth.

All of the students go back to Earth willingly except for Rod, who has great difficulty reverting from the status of head of a small but sovereign state to a teenager, who is casually brushed aside by the adult rescuers. However, his teacher (and now brother-in-law) and his sister persuade him to change his mind. His teacher also informs Rod that his warning against "stobor" ("robots" spelled backwards) was just a way of personalizing the dangers of an unknown planet to instill fear and caution in the students, as all students receive the same warning, regardless of the planet they are sent to for the final exam.

Years later, Rod is briefly depicted accomplishing his heart's desire. The novel's ending finds him preparing to lead a formal colonization party to another planet.

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. The numerous political crises of the fledgling colony illustrate the need for legitimacy in a government appropriate for the society it administers, another common theme in Heinlein's books. 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. Unusual for science fiction at the time, but quite typical of Heinlein's works, the novel portrays several competent and intelligent female characters.[1]

Heinlein Society member and researcher Robert James has noted that Heinlein wrote a letter in which he "firmly states" that Rod Walker is black.[2] According to James, "The most telling evidence is that everybody in 'Tunnel' expects Rod to end up with Caroline, who is explicitly described as black."[2] In recognition of this, the cover illustration of a Full Cast Audio version of the work was revised to "show Rod with his correct ethnicity."[3]

Rod is at one point referred to by character Jock McGowan as a "cholo", a derogatory term for someone of Latin American ancestry.

• Tunnel in the Sky title listing at the Internet Speculative Fiction Database
• Tunnel in the Sky at Open Library