You who stand before us
One of Terry Pratchett's earliest novels, The Dark Side of the Sun explores a science fiction setting, although astute readers will note the appearance of several concepts later to appear in Discworld.
Dom Sabalos is the heir to the throne of the planet Widdershins, a human colony in a galaxy where there are 52 intelligent races - but oddly all of them inside a sphere 200 light-years in diameter, centered on Wolf 359. Besides this, there are also bizarre stellar phenomena and mysterious towers strewn across the region that speak of Precursors, known as the Jokers. The mystery underlying the setting is where the Jokers went, the only clue being the poem shown above, which was found on one of the towers.
A secret arm of the human government, using "probability math" to predict the future, tries repeatedly to assassinate Dom but the universe always conspires to save him for some purpose: which, of course, is to find the truth behind the Jokers' disappearance...
- Actually, That's My Assistant: Early in the novel, Dom has two people (a man and a battered antique Class One robot) pointed out to him as Charles Sub-Lunar, the greatest genius of the age, and his manservant. It's not until much later that he finds out that Charles Sub-Lunar was the robot.
- All the Myriad Ways: After studying probability-math (which is like psychohistory but less so), Dom acquires an ability to sense the Alternate Universes where he dies, and take steps not to be in them.
- Assassin Outclassin': An important element of the plot. Due to probability mathematics (see the All the Myriad Ways example above) Dom can do this.
- Bilingual Backfire: Joan knows some phnobe (though not enough to speak it).
- Bizarre Alien Biology: explored quite a bit.
- Bizarre Sexual Dimorphism: Sort of. The phnobes have three sexes, so they're presumably sexually trimorphic -- this is mentioned but not explored further. The swamp igs are hermaphrodites, while the drosks are born male but become female 1/3 of the way into their life.
- Born Lucky: Not exactly; here it is a learned ability. Extreme luck is a side effect of learning probability mathematics. Maybe. It is possible to build a lucky robot, however.
- Chekhov's Gunman: subverted. Charles Sub-Lunar and his assistant are lurking in the background of a number of scenes, but do very little.
- Comically Missing the Point: Dom's coronation breakfast is supposed to be the same as the simple, austere one that the puritan, anti-waste religious figure Arte Sadhim ate before he became Lord of Earth. However, inevitably each simple item is acquired by some enormously expensive means as he's royal (for example, the glass of water was melted off a comet).
- Encyclopedia Exposita: Several, mostly the works of Charles Sub-Lunar.
- Expospeak Gag: Several involving the robots. Particularly neat is the scene where Isaac defeats a gang of other robots, which outnumber him but have less sophisticated electronic brains, but informing them that they're not robots, they're "recumbent waterfowl of the genus Anatidae", and then knocking them out while they're trying to work out what he just said. ("I repeat, you are all sitting ducks.")
- Fantastic Caste System/alien subspecies: While considered a Superior Species in general, the Creapii are divided by caste depending on their living temperature and their size. Once there were only "low degree" Creapii, but in half a million years they created the middle-degree variant, and then other subspecies followed. Low-degree Creapii evolved on a planet warmer than Venus, but less hot and barren then Mercury sun-side. High-degree ones can survive on some of the cooler stars.
- Fantastic Racism: Referred to as "shape hatred." Some humans refer to phnobes as "gecky frogs". This is not a good thing to say.
- From a Single Cell: The Widdershins googoo (the name is a reference to googols) can regenerate someone's entire body working from just a fragment of brain, which is what happens to Dom after an assassination attempt with a black hole.
- Genius Loci: The First Sirian Bank is a sentient planet, Chatogaster is a sentient sea, and there's a brief mention of a sentient sun having been found elsewhere. "We are now looking for an intelligent gas cloud to complete the elemental quartet".
- Humans Are Special: Dom's grandmother is convinced the Jokers' World was Earth and they bred with humans to uplift them. Others pointedly mention that identical theories are believed by just about every other race about their own homeworld.
- Hyperspace Is a Scary Place: Interspace contains infinite possibilities, meaning unless your ship is shielded you get constant glimpses of distant universes and timelines.
- I'm a Humanitarian: Cannibalism is common practice among the Drosks; the other races tend to avert their eyes when seated at the same table with them.
- Incredibly Lame Pun: Noted in-universe. The planet Band is so-called not only because it consists of horizontal bands of different kinds of terrain, but also because landing there is banned.
- Made of Indestructium: The Joker towers are completely unmarked by anything. Creapii once tried a superweapon which wrecked several nearby star systems, but the tower was unaffected.
- Million-to-One Chance: Sometimes happens due to extreme luck of some characters. For example, robot assassin Ways in order to prove his identity has to throw three six-sided dice and get three sixes - twice in a row. (That's only a 1 to 46656 chance, of course, but the principle stands.)
- Morph Weapon: The memory sword.
- Never Bring a Knife to a Gun Fight: Never bring a single-shot stun gun into a place where every alpha male is armed with a two-foot-long knife. See also: Too Dumb to Live.
- Never Mess with Granny: Don't cross Joan Sabalos.
- Production Foreshadowing: The First Sirian Bank speaks in the same block capitals as Death from the later Discworld series.
- The Reptilians: The phnobes, complete with hisssing sspeech.
- Ridiculously-Human Robots: Ways, the Class Five assassin robot designed to resemble a human.
- Sdrawkcab Name: A star called 'Rats' with a planet called 'Tenalp' is briefly mentioned - aside from being very strange (and not the sort of thing you mention in mixed company), we don't hear exactly why they're so called.
- There's a brief mention of them having "negative entropy", which could suggest that natural processes work in reverse, hence the names.
- Sharpened to a Single Atom: Until the blade shatters when used against a villain gifted in luck manipulation.
- Shout-Out: Dom's robot sidekick is named Isaac.
- Space Whale: The Sundogs, huge intelligent life-forms native to space who can travel naturally through Interspace and will carry ships with them for a fee. They lay their eggs on the planet Band and their young grow up on the surface, being only man-sized when born.
- Sssssnaketalk: The phnobes.
- Starfish Aliens: Dom says most of the alien races are incomprehensible to humans, mentioning the Jovians and the Spooners specifically. The Creapii are comprehensible but are a more literal example, being many-tentacled in their native form. Mentally, however, anything but incomprehensible - or rather don't act incomprehensibly: high-degree Creapii have deep enough understanding to be very human with humans, very phnobe-like with phnobes, etc. Which is probably why...
- Superior Species: The Creapii are said to be 'Superhuman', which humans (a term which now includes two other sentient species with similar cultures, and some particularly advanced robots) do not appear to object to.
- Swiss Army Gun: The Memory Sword.
- "Three Laws"-Compliant: Parodied. Mention is made of the "Eleventh Law of Robotics, Clause C, As Amended", which states that a robot may use necessary force if explicitly instructed to do so by its authorised user.
- Too Dumb to Live: "Intelligence is humanity's prime survival trait. Therefore it is as well that those who don't show it be weeded out."
- What Happened to the Mouse?: The robot assassin Ways, who was an antagonist for almost all the book, is forgotten near the end, and his fate is unknown.
- What Measure Is a Non-Human?: Invoked when it's mentioned that "Human" is a legally defined term for a limited subset of intelligent species, including some robots and a planet-sized computer known as the First Sirian Bank. Essentially it's a clear measure of what a Non-Human is.