%%* CrowningMomentOfAwesome: The Last Question
* DeathOfTheAuthor: One of Asimov's favorite stories, "The Martian Way", was a way of using his claustrophilia as an attack on Joseph [=McCarthy=]. In it, a [=McCarthy=] counterpart named "Joseph [[NamesToRunAwayFromReallyFast Hilder]]" is almost able to become Global Administrator at the cost of space development. Nuclear "proton micropiles" are used to produce energy almost for free, and are used in pumped steam rockets to colonize the solar system - so Hilder whips up [[YouCanPanicNow scare reports]] on how space travel will eventually turn the Earth into a desert. Asimov's Martians, being immune to SpaceMadness due to their upbringing as claustrophillic SpacePeople, are able to make a three-year trip to Saturn, retrieve a cubic mile of ice from its rings, and return in time to make a complete fool of a visiting bureaucrat who previously stated for the record that Earth cannot spare a single drop of its ''one and a half quintillion[[note]]'''1,500,000,000,000,000,000'''[[/note]] tons of water''. As an attack on [=McCarthy=], it flopped. As a modern-day attack on environmental alarmism, it ''works''. The ironic part is that ''Asimov was an outspoken environmentalist.''
* FanonDiscontinuity: ''Foundation and Earth'' is basically just an excuse for a big crossover with the Robots series and doesn't make much sense compared to the earlier Foundation books.
* HarsherInHindsight: "Trends", one of his earliest short stories, is really uncomfortable to read at any time from the 1980s onward. When it was written in 1939, the idea that a plurality of Americans would deny science outright in favor of religious fundamentalism, and be a powerful lobby, was ludicrous. Nowadays, the controversy shows up in state governments every few years. Moreover, in the story, [[spoiler:the mob comes to its senses after the hero risks his life to go into space]]. In reality, fundamentalists, being ''fundamentalists'', never change their mind no matter how much evidence they are confronted with. Asimov himself lived to see some of this: in the 1980s, he, along with several other scientists, wrote an essay presenting the facts and exhorting the public not to fall for creationism. [[FailureIsTheOnlyOption It didn't work.]]
* ScienceMarchesOn: When robots and computers actually arrived, they didn't work anything like he predicted (though it's worth noting that most other writers of the time were even ''more'' off base). People reading it today might mistakenly think this is a mistake on his part; obviously, it isn't, since there was nothing to use for reference at the time. When he started writing, basic computer theory was still being developed, and the electronic computer hadn't been invented yet. Notable especially for what he thought would be easy and what would be hard are quite different. He thought in 2061 we'd still be using vacuum tubes but have self-aware AI. He didn't think the equivalent of a modern integrated circuit chip would be invented until after tens of thousands of years of refinement.
** To the point where he wrote about pilots plotting hyperspace courses using sextants, reference books and slide rules. On the other hand, while computers were still room-filling behemoths, he envisioned a society in which no one learned to do basic math because everyone had cheap, portable calculating devices.
** This trope only applies to his fiction, though, as all his non-fiction writings about science, especially his chemistry works, are considered to have been very accurate and consistent with contemporary understanding.
** In ''A Pebble in the Sky'' there's an extended section describing the role of proteins as genetic material. The book was published in 1950, two years before the definite experiment which proved that DNA was the genetic material.
** One short story centered around the fact that only one suspect would consider outside of a building to be a safe place to hide undeveloped film, the researcher who lived on Mercury, which had no day/night cycle and therefore would not recall that the sun rises on Earth and would ruin the film. A few years after that was published, astronomers proved that Mercury did rotate (albeit very slowly, three times per year, producing one local day every two years), unintentionally making this ConvictionByCounterfactualClue. Later printings included author's notes to the effect that he wanted to fix this but couldn't figure out how to do it without rewriting the entire plot.
** Whenever this happened, he joked that the scientists should have gotten it right to begin with, and he didn't see why he should have to change his work because of their mistakes.
%%* TearJerker: The Ugly Little Boy