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Literature / The Caves of Steel

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A 1954 Science Fiction/Crime Fiction novel by Isaac Asimov, and the first novel in his "Robot trilogy".

Caves of Steel takes place in a future New York City. On the overpopulated future Earth, cities are gigantic metropolises encased under steel domes where people live in cramped conditions and subsist on processed food, never seeing the sky. In contrast, the Spacer worlds—human-colonized planets which severed political ties with Earth long ago—are utopian locales of low population, plentiful resources, massive military power, and economies based on the widescale use of robots for manual labor.

It is in this New York that a murder is committed: the victim is a Spacer, one of the residents of Spacetown, the Spacer enclave in New York. It is suspected that one of the motives was anti-robot sentiments; the victim was a roboticist who was working on the large-scale introduction of robot labor into Earth's economy, a desire opposed by most of the populace — sometimes to the point of terrorist aggression. If the murderer is not found — fast — a major diplomatic incident looms.


The investigator is Elijah "Lije" Baley, whose Spacer-assigned partner will be an android, R. Daneel Olivaw, a new type of robot (designed by the murder victim no less) which is externally indistinguishable from a human. The opposition between Lije's impulsiveness and unorthodox methods, and Daneel's pure logical thinking and adherence to the law and procedure, is a theme throughout much of the book. Another theme is the nature of the society of Earth's Cities and how stable it is in the long run.

The Caves Of Steel was followed by two sequel novels, The Naked Sun and The Robots of Dawn (and a short story, "Mirror Image", set between the two). After the resolution of the first case, Baley's reputation leads to him traveling to the Spacers' homeworlds to work with Daneel in solving other murder cases with wider political implications.


The series reached a finale of sorts in Robots and Empire, set two centuries after The Robots of Dawn; the story mainly served to merge Daneel's story into the Myth Arc of Asimov's "Galactic Empire" and Foundation stories.

This story was adapted for a VCR game by Kodak in 1988 (with elements of The Robots of Dawn added in and a character sharing a name — only the name — with one from Robots and Empire). You can watch the movie itself on YouTube here (the cards required for the game can be found here), as well as a review/riff by The Spoony One here.

The novel provides examples of:

  • Abandoned Area: The motorways, an underground tunnel-network for vehicles. The introduction of moving pedestrian conveyor-belts made civilian cars obsolete, so the massively-overbuilt system is now used only by police, firefighters, and other high-speed civil transport.
  • Agony Beam: The police are equipped with neuronic whips as a less-than-lethal way of dealing with criminals.
  • Always Someone Better: Lije is a C-5 Plainclothesman (Detective) with a long history in the department and the respect of his peers, but Daneel is stronger than Lije, smarter than Lije, and never needs to rest or eat. Lije has to worry about the robot solving the case before him, and every aspect of the robot's superiority is seen as a threat to his job.
  • Androids and Detectives: As the Ur-Example, it established many of the conventions of this trope despite the lack of many traditional Cyberpunk elements.
  • Androids Are People, Too: Part of the plot is Elijah Bailey, our protagonist and someone prejudiced against robots, learning to treat Daneel, a robot, as an equal.
  • Artificial Human: Daneel, who is a revolutionary (and controversial) first generation "humaniform" robot. He is designed to pass for human and can even eat (although he does not actually digest the food, just stores it in a sack for later disposal). His personality could use some work though, since the fact that he is The Spock can be a giveaway that he is not really a human.
  • As the Good Book Says...: An ongoing theme is that Earthmen are familiar with the Bible but Spacers are not.
    • Elijah and his wife Jezebel have meaningful names. The biblical story is referenced when she is introduced, and Jezebel's character is an important part of her personality.
    • Lije tells the story of Jesus and the woman taken in adultery to Daneel about the subtleties of the word "justice". At the end, Daneel uses the exact words "Go and Sin No More".
    • Lije remarks that Dr. Sarton created R. Daneel to his own image. Then he remarks that Daneel doesn't get the reference because the Bible is not a popular book among Spacers.
  • As You Know: Characters spend a lot of time explaining the Three Laws of Robotics to each other.
  • At Least I Admit It: Of the "At least you admit it" variety. Dr. Fastolfe likes Elijah because he is direct and upfront about his dislike of the Spacers, while politicians like Enderby also dislike the Spacers but always handle them and disguise their resentment with politeness.
  • Author Appeal: The crowded underground cities of Earth would be hellish to a claustrophobe, but Asimov was a claustrophile. He stated that it had never occurred to him that other people might find the closed-in cities undesirable. Spending their lives in these Cities has made this condition much more common in the population, and fear of wide open spaces has become the societal norm on Earth.
  • Batman Gambit: The Spacers (or at least Sarton and Fastolfe's faction) were deliberately trying to destabilize Earth's economy by "encouraging" the use of robots. They wanted to create a large population of unrooted, dissatisfied people who would be willing to become the foundation of a new wave of colonists, avoiding the flaws of both Earth and Spacer societies.
  • Big Applesauce: New York, where the story takes place, has turned into one of a handful of mostly-underground metropolises that now house the entirety of Earth's population.
  • Born in the Wrong Century: There are plenty of "medievalists" in the future who long for better days of the Medieval Era, which by this time refers to the Late Twentieth/Early Twenty-First centuries. Most of the people of Earth are medievalists in one fashion or another, usually manifesting itself in some minor personal foible. Elijah himself likes to read a lot about the old days, and Enderby, Lije's boss, uses such bizarrely anachronistic things as windows and eyeglasses. There are rumors of more serious subversive organizations that want to dismantle the Cities and return to the earlier ways of life, but Lije does not take them very seriously. The subversive medievalists really do exist, and in fact were planing some sort of popular uprising in the near future if they could not get their way through political pressure.
  • Can't Bathe Without a Weapon: Police regulations require Elijah to keep his blaster with him at all times, even in the shower (in a waterproof holster). He claims he can still draw and fire it in under five seconds.
  • Chekhov's Gun: At the very beginning of the book, Lije notices that Enderby is wearing new glasses, as he broke his old pair. At the end of the novel, this seemingly random bit of information ends up becoming the piece that puts the whole case together for Lije.
  • Chekhov's Gunman: R. Sammy.
  • Concepts Are Cheap: Played with. When told that Daneel is programmed with a "justice circuit," Elijah claims this is impossible because justice is too abstract a concept and hard to define. However, Daneel has a much simpler definition of justice, "That which exists when all laws are enforced." He does develop a more nuanced view by the end of the novel.
  • Covers Always Lie: The depiction of New York City on at least some editions of the novel give the impression of it basically being lots of skyscrapers, with plenty of large open spaces hundreds of feet high and wide, only with an (unseen) roof. That is at odds with the actual description in the novel, where even the areas 'outside' buildings have walls and tunnels and coverings. Even windows are a rarity.
  • Cranial Processing Unit: Inherent to all robots.
  • Cyberpunk: The City anticipates the dystopian urban landscape of Cyberpunk, almost 30 years before Blade Runner and William Gibson, but it was not necessarily intended to be dystopian. The idea of a vast, totally enclosed city did not bother Asimov at all, who would have liked the enclosed spaces.
  • Domed Hometown: All of Earth's population live in Cities (areas such as New York, Baltimore, and Washington grew into a single city), areas enclosed under massive domes. This is tied to humanity developing a neurosis about the open air. The underground cities of Earth were built for greater efficiency under the conditions of serious overpopulation.
  • Dropped Glasses: The chief dropped and broke his glasses when he discovered the body of the victim. This proves critical to solving the case.
  • Early Installment Character-Design Difference: In this first book, Daneel's eyes are brown; in The Naked Sun, his eyes are blue.
  • Eating Machine: Daneel, thanks to a compartment hidden within his stomach, all to better impersonate a human. He does not derive any actual nutrition from the food, and needs to regularly empty his stomach sack to prevent the food from spoiling and emitting an unpleasant odor. Daneel says he didn't really chew it and he doesn't salivate, so the food is still entirely edible when he removes it from his food sack. He offers it to Lije, but Baley refuses.
  • Easily Forgiven: Baley's first attempt at The Summation turns out to be a disaster, and he fully expects to be taken off the case given the need to avoid antagonising the Spacers. However the Spacers are impressed that Baley was willing to talk straight with them, and insist he stay on the case. Commissioner Enderby also isn't annoyed, because he was relieved that Baley was so off target about what really happened.
  • Elves Versus Dwarves: While both are human beings, the Spacers and Earthmen share many stereotypes of elves and dwarves, respectively. The Spacers are proud, elegant, long-lived people with superior technology while the Earthmen are conservative cave-dwellers. The main conflict of the story is between these two factions.
  • "Eureka!" Moment: Elijah figures out the answer to the mystery when Daneel casually brings up Enderby's glasses. Daneel has a different one when he begins to grasp the distinction between 'legal' and 'ethical'.
  • Explain, Explain... Oh, Crap!: When Life and Daneel visit a premier roboticist, Lije asks him about Ridiculously Human Robots, how they would be different from humans, and how easy it is to spot them. The man starts to confidently say how unlikely it is, then pauses as he realizes that Daneel meets the signs he just described. The man is embarrassed that it took him so long to notice.
  • Extreme Speculative Stratification: Earth is an overpopulated, poor planet with resources running out, and forced to implement Population Control, life in megacities, Future Food Is Artificial and Fantastic Caste System in order to survive. It is surrounded by fifty Spacer worlds; wealthy, low population, dozens of robotic servants per person...
  • Fairplay Whodunnit: Largely written to prove a Science Fiction Fairplay Whodunnit was possible, in defiance of one of the rules of Fairplay Whodunnits about technology.
  • Fantastic Racism:
    • Robots are addressed as "boy," lack permission to travel in the high-class means of transportation and are treated with general contempt by Earth's inhabitants. One of the major bones of contention is that they have come to Earth and are taking jobs away from the local humans. Significantly, R. Sammy may have been named for a racial slur once used to describe people from India.
    • Spacers view earthlings as primitive, disease-ridden savages, and in turn earthlings resent the Spacers for their long lives, wealth and luxury.
  • Flying Dutchman: The legend of the Wandering Londoner is apparently a well-known myth of the era in the style of the Wandering Jew version of the myth: A criminal who tried to find a hiding spot where he planned to wait out the manhunt got lost in the tunnels beneath London, and is still to this day wandering in search of his sanctuary.
  • Genre-Busting: Sci-fi robot detective stories.
  • Go and Sin No More: Said word-for-word by Daneel to Commissioner Enderby.
  • Have You Told Anyone Else?: Elijah makes sure to have the Commissioner listening in remotely when he goes to confront the Spacers with what he thinks is a conspiracy. He's wrong, and ironically the Commissioner is the real murderer. When Elijah confronts him, he has Daneel with him to relay what's happening to the Spacers for the same reason.
  • Hive City: Earth's population lives in eight hundred immense, domed "Cities" with an average population of around eleven point two million, which the growing pressure to utilize the enclosed land as efficiently as possible has filled with extremely dense urban growth. The result is that each city has become a forest of windowless, interconnected towers hundreds of stories high and of buildings larger than modern city blocks. Their inhabitants spend their entire lives enclosed within these giant sprawls of architecture, to the point that they've started to develop an aversion to open spaces and even windows — an echo of the more pronounced habits of their City Planet-dwelling descendants in the Empire and Foundation novels. This is in contrast to the Spacers of the offworld colonies, who live in exponentially less dense populations and like to spread out where Earth folk build close and high — the Spacer neighborhoods in Earth cities consist of single houses and cultivated land each under its own dome, a practice that the Earth natives find very bizarre.
    Even dimmed by the weather, the City was a tremendous thing to see. The Police Department was in the upper levels of City Hall, and City Hall reached high. From the Commissioner's window, the neighboring towers fell short and their tops were visible. They were so many fingers, groping upward. Their walls were blank, featureless. They were the outer shells of human hives.
  • In the Future, We Still Have Roombas: The reason this is averted is because a humanoid robot can use technology designed for humans, which is cheaper than constructing purpose-built robotic machines that would still require expensive positronic brains.
  • Ironic Name: Elijah and Jezebel are Biblical figures that were vicious enemies, whereas the Elijah and Jezebel (Jessie) of this story are a Happily Married couple. (There is, or was, a bit of conflict over their names: she enjoyed the implications of being a "bad girl" without actually needing to be one, until he burst her bubble with his idea of what might have 'really happened' behind the stories.)
  • Job-Stealing Robot: A major part of the plot is people rioting against robots replacing them. This turns out to be deliberate; the Spacers want Earth to have large numbers of jobless, hoping they will search for opportunities elsewhere and therefore launch a new wave of planetary colonization.
  • Jurisdiction Friction: Inverted, nobody wants the case. Baley points out that the Terrestrial Bureau of Investigation could seize the case based on its global implications, and the Spacers could assume control with their influence in the government. Enderby retorts that the TBI doesn't want the responsibility, and though he doesn't know it at the time the Spacers are more interested in investigating the sociology and psychology of the Cities than they are with solving the crime itself. Ultimately, it gets dumped on the New York City police because Spacetown is officially in their jurisdiction and they have no way of avoiding it.
  • Kryptonite Factor: Robots have a singular physical weakness: gamma radiation, which will destroy a positronic brain at doses well below what humans can tolerate. It is not common knowledge on Earth, but Daneel informs Baley since, being partners, it is important that Baley know his weaknesses.
  • Lie Detector: "Cerebroanalysis" is a technique that the Spacers use to gauge mental status and general personality. As a self-contained unit, Daneel is able to determine, simply by being in the same room, that Commissioner Enderby does not have the capacity to commit premeditated murder, thus eliminating him as a suspect. Since Enderby had not intended to kill Dr. Sarton, and had actually meant to shoot Daneel, his analysis is both correct in its read of Enderby but wrong in the results.
  • Living Lie Detector: Daneel is one, though he is not technically living. He can perform "cerebroanalysis" with people in close proximity, a technological gauge of mental status.
  • Lying Finger Cross: Elijah instinctively crosses two of his fingers when he proposes that Commissioner Enderby accompany him to Spacetown, since he is secretly hoping that Enderby will decline.
  • Male Restroom Etiquette: There is a strict privacy taboo in the male communal showers and restrooms such that no one speaks to anyone else in the Men's Personals, nor looks at them nor acknowledges each other's presence in any way. Elijah has to make a deliberate effort to force himself to speak while still in the antechamber, and he recalls a time as a child when he was beaten by his uncle after he had stubbed his toe and accidentally cursed aloud. Women's Personals are quite the opposite and are seen as a social meet-up place.
  • Manic Pixie Dream Girl: Jessie was when she and Elijah met, but she has mellowed by the time of the novel itself.
    "Oh, goodness," (Jessie) said, "what if you do look like an awful lemon? I know you're not really, and I guess if you were always grinning away like I do, we'd just explode when we got together. You stay the way you are, Lije, and keep me from floating away."
    And she kept Lije Baley from sinking down.
  • Mega City: The population of Earth lives in a cluster of cities that average 11.2 million souls each. The governments of three large cities (New York, Philadelphia and Washington) are considering merging into one single Mega Mega City, but the logistics of maintaining and governing such a large conglomerate have so far prevented any action on the plan.
  • Modern Stasis: Really, once you get past the idea of underground cities and robots, the culture of Earth does not seem very different from the mid-20th Century. For example, Elijah observes that men are studiously non-conversational in the restroom, whereas women love to gossip in there. Gender roles in particular are very much the same as during the time when the book was written. The society simply seems less prosperous, rather than genuinely different, than real world America at that time. Only the Spacers have culture and technology that seem genuinely different, and even then there is a lot of Zeerust.
  • More Than Mind Control: During his first visit to Spacetown, Fastolfe discusses his project to encourage Earthlings to begin colonizing again. Baley keeps thinking about the topic through the rest of the book. When Daneel announces that the Spacers are cancelling the investigation, he mentions that Fastolfe had dosed with him a drug to make him more "receptive" to the sales pitch. Although the initial hope was to turn him into a zealot, the drug could not make Baley believe anything "foreign to the basis of his thought", and his practicality prevented any strong results. At least right away; Baley eventually converts to Fastolfe and Sarton's cause of his own free will.
  • Murder by Mistake: Baley assumes Dr. Sarton's death was an accident when the Commissioner first talks about a "death" happening in spacetown. In fact Dr. Sarton's death was accidental — he was killed by a shot intended for R. Daneel (who was built to resemble his creator).
  • Never Accepted in His Hometown: Robots were created, developed and mass produced right on Earth almost three thousand years before the beginning of the novel. They were integral in the technological revolution that lead to space-travel, food for the whole planet and world peace, but they were never accepted into Earth society and were completely banned from the planet soon after their creation. It is only through the direct intervention of the Spacers, who have completely integrated robots into their way of life, that they are even beginning to merge with the Earthlings.
  • Nondescript, Nasty, Nutritious: The most unfortunate citizens of future Earth's vast subterranean cities get rations of yeast mush. Vat-grown yeast is the foundation of the cities' food system, but most people get food that's a few steps removed from it or at least better-prepared.
  • "Not So Different" Remark: Elijah mentions that although Jezebel was ruthless in her fight against her rival religion, the biblical Elijah was too, and both had a lot of people killed.
  • Not with the Safety on, You Won't: Elijah is understandably disturbed when the ostensibly Three Laws-Compliant Daneel resolves the potential riot at the shoe store by threatening to use a lethal weapon. Daneel explains to his partner that the weapon was not loaded, had never been loaded, and was not even fully assembled. If it had been otherwise, it would have been possible for him to accidentally injure a human being, something Daneel finds unthinkable. He even points out that he only has the dummy weapon in the first place because not carrying one would be an obvious indication that he is not the human Police Officer he is pretending to be.
  • Obnoxious Entitled Housewife: The female customer at the shoe store, who raises a huge fuss over being served by a shop robot rather than a human. And then verbally attacks the store's owner for the "offense" of having robots as staff, and Lije and Daneel, for trying to reason with her. Only to quail and protest that it's not her doing when her complaints nearly incite a riot.
  • One Riot, One Ranger: When facing a potential anti-robot riot, Daneel insists on repressing it himself instead of waiting for a squad car. He does with a Brandishment Bluff, threatening to use deadly force even though he is Three Laws-Compliant. As no-one knows he's a robot, no-one is willing to call his bluff.
  • Only Electric Sheep Are Cheap:
    • Natural (non-processed) food is a luxury good, to such an extent that when Baley eats a real apple, he finds it disconcerting even before he bites right into the core and gets a mouthful of seeds. Apple, in his view, comes in the form of a sauce or paste, not some weird orb that was probably dangling off a tree (or, he wrongly assumes having never seen an apple, buried in the ground) a few days ago.
    • As for animals, children visit the zoo for the privilege of seeing actual, living dogs, cats, and sparrows.
  • Outgrown Such Silly Superstitions: The Spacers have abandoned religion long ago. Lije, meanwhile, can quote Scripture from memory, but exactly how religious he actually is isn't clear. Both are probably something of an Author Avatar, since Asimov was an atheist, but raised Jewish and was very well read on the Bible (among many other topics).
  • Out-of-Character Alert: Baley is told that Jessie is associating with unsavory people. He knows it isn't true because she supposedly provided her full name as "Jezebel", a name that Jessie avoids using.
  • Pick Your Human Half: Daneel has humanlike appearance and robotic psyche.
  • Poke the Poodle: Elijah's defense of the Biblical Jezebel destroyed his wife Jessie's self-image as a naughty girl. So to prove herself, she joins the revolutionary Medievalists... or at least a society they operate for bored housewives that meets for snacks and the occasional revolutionary speaker.
  • Population Control:
    • Earth's enormous population is only barely managed, and the quality of life, while not terrible, isn't very appealing. It is shown that producing enough food to feed the population is an ongoing challenge where even small missteps can result in starvation.
    • The Spacers have the opposite problem, with a population that is small, affluent, but completely stagnant. Dr. Fastolfe's plan to encourage Earth to settle the galaxy is a solution to both Earth's overpopulation and the Spacers' inability to expand.
  • Poverty Food: A double case. The lowest classes on Earth have to substitute on some bland yeast mush. However, even for the rest, due to Earth being poor and overcrowded compared to the rich and spoiled Spacers, natural food is always eaten processed, and only in Spacer cuisine does one encounter things like whole apples, eggs with visible yolk, etc.
  • Really 700 Years Old: The Spacers have a very long life expectancy, much to the surprise of Earthlings who think them younger than they are.
  • Reassigned to Antarctica: Declassification. If you are deemed unfit for your job, or your field itself is rendered obsolete, you lose your rating (A combined social/economic scale that determines housing, income, food, etc.) and are given menial busy work to justify the subsistence-level rations and housing the government gives you. Elijah still vividly remembers when this happened to his father, and how his family was destroyed in the aftermath. The fear of going through this is a constant threat throughout the case.
  • Red Oni, Blue Oni: Baley is red to Daneel's blue. Though Baley is still a rational thinker by necessity of his job, his preference for intuition and inductive reasoning are a clear contrast to Daneel's uncomplicated, black-and-white logic. Daneel's observations of Baley over the course of the trilogy are largely responsible for tempering his robotic mind into something more flexible and accepting of nuance.
  • Revealing Cover-Up: The "murder" of R. Sammy is initially theorized to be an attempted cover-up by Baley himself to cover Jessie's membership in the Medievalist organization but Baley then figures out that it was Enderby trying to cover up that he was the Spacetown murderer and had used Sammy as an accessory.
  • Robot Me: Daneel was made to be identical to his creator. This becomes the basis of one wrong theory on the part of Lije and is the critical component in solving the murder — the murderer was after Daneel and accidentally shot his creator instead.
  • Rule of Threes: Elijah thinks he's solved the crime three times, but he's only right the third time. 1) There was no murder, only a Spacer conspiracy — the Spacers destroyed a robot lookalike and Daneel is actually Dr. Sarton pretending to be a robot. 2) Daneel isn't bound by the Three Laws and committed the murder. 3) The murderer meant to destroy Daneel, but killed Dr. Sarton by mistake.
  • Sarcasm-Blind: When Daneel explains why the Spacers are trying to help Earth change, Elijah asks sarcastically if they're just doing this out of the kindness of their hearts. Daneel explains that there is self interest involved, but it's nice of Elijah to attribute such motives to them.
  • Super-Powered Robot Meter Maids: Averted; at one point Jessie worries that Daneel is listening in on their conversation. Elijah says that any unusual abilities would hamper Daneel's ability to pass as human, but internally he admits that this is mainly conjecture on his part.
  • Sympathetic P.O.V.: Discussed in-universe, Elijah tells Jessie that the Biblical Jezebel was written from the point of view of her enemies, or she would probably be much more sympathetic if we had seen her point of view.
  • Terrified of Germs: The Spacers are paranoid about being infected with human microbes. On their utopian planets they have no disease and their immune systems have atrophied as a result.
  • They Fight Crime!: One's a police detective with a terror of open spaces, and the other's a prototype colonist android. And they fight crime.
  • Title Drop: "Caves of Steel" is a nickname for Earth's enclosed, mostly underground metropolises, in which the entire population lives.
  • To Be Lawful or Good: Understanding that the conflict even exists, much less wrestling with it, is a big part of R. Daneel's Character Development. See Concepts Are Cheap, above, with respect to his views on "justice". Early on, Daneel considers the phrase "an unjust law" to be an oxymoron — justice is the enforcement of the Law, therefore a law cannot possibly be unjust.
  • The Un-Smile
    R. Daneel smiled. The gesture was sudden and surprising. His lips curled back and the skin about either end folded. Only the mouth smiled, however. The rest of the robot's face was untouched.
    Baley shook his head. "Don't bother, R. Daneel. It doesn't do a thing for you."
  • Uncanny Valley: In-universe, one of the reasons why robots — at least the current generation — are so unpopular on Earth; they are clunky mechanical units with disturbing facsimiles of permanently-smiling human faces on their "heads." Daneel is an attempt by his creator to avert this.
  • Underground City: Of the artificial kind. While the Cities extend well above ground, they are sealed underneath domes and designed with a minimal amount of open space in their interiors (hence the name "The Caves of Steel"). Most Earth humans are severely agoraphobic and cannot tolerate even brief exposure to the outdoors without having a panic attack.
  • We Are as Mayflies: Played with. The Spacers who want to renew mankind's expansion see the short lives of Earthmen as ideal for the task — the young are more ambitious and willing to step outside social convention, and with "only" fifty years of future lifespan at risk, are more tolerant of danger than those who can confidently expect to pass three hundred years of age.
  • We Will Have Perfect Health in the Future: Most notable in the friction between Spacers and Earthmen. Earthers have lifespans comparable to 20th century Americans, while the eugenically-perfected Spacers tend not to experience "middle age" until turning 250 or so. They enforce this with careful control of the microbes introduced to their worlds from Earthers, and look down on the filthy, disgusting, shortlived Earthmen. The Spacers' weakened immune systems mean that when an Earthman visits, the visitor has to be thoroughly sterilized and most of the Spacers wear gloves and nose-plugs and keep their distance.
  • We Will Use Manual Labor in the Future: A major source of contention between Earthlings and the Spacers is the refusal of Earth to stop using manual labor. Robots could do all the work better, faster and safer for only a fraction of the cost, and are one of the key reasons for the Utopian societies of the Spacers, but their introduction to Earth society is being resisted (sometimes violently) because they will displace so much of the human workforce.
  • When the Clock Strikes Twelve: Near the end of the book, Daneel notifies Lije that, since he's gathered the information Fastolfe wanted about Earther society, the investigation is being ended that day. Desperately worried about the consequences failure would have for his career, and with a brand-new "Eureka!" Moment running through his mind, Baley convinces his robot partner that the wording of the order can be construed as meaning they're still on the case until the day actually ends at midnight. Sure enough, they manage to extract a confession from the murderer right at the stroke of 12.
  • Women's Mysteries: For women, public Personals are a major socialisation and gossip hotspot. For males, the custom is to not even look at other men when using the facilities.
  • Won't Take "Yes" for an Answer: When Elijah plans to visit Spacetown, he expects Enderby to insist on accompanying him and plans to maneuver him into agreeing to trimensional presence instead. When Enderby instead flat-out refuses to go to Spacetown and only agrees to trimensional presence after Elijah suggests it, Elijah is confused at getting exactly what he wanted so easily when he expected to have to persuade and argue Enderby into agreement.
  • Zeerust: At one point, Elijah reminisces about anti-Spacer riots and recalls a protest song based on an old folk tune with the nonsense lyrics "Hinky-dinky-parley-voo". The song, Mademoiselle from Armentieres, was from World War I, and has faded from cultural consciousness to such a degree that it is was all but forgotten within half a century of this novel's publication. Not to mention that, by the standards even of the late twentieth century, let alone three thousand years in the future, when this story is set, the song is hopelessly quaint.