A novel by Creator/RobertAHeinlein, first published in 1958. Widely considered to be one of the best of his young adult novels.

Set TwentyMinutesIntoTheFuture (of 1958, that is), the plot centers around Kip Russell, a young man who wins a used space suit by writing a whole bunch of advertising jingles for Skyway Soap. (He was hoping to win a trip to the moon. The spacesuit was the consolation prize.) After spending a great deal of time and energy restoring it, Kip decides to sell the spacesuit to help pay for college. He takes it for a final drive first -- unfortunately, this results in him being kidnapped by a reptilian alien he ends up calling Wormface. The alien is also holding captive a little genius girl named Peewee and a strange, mink-like creature Kip calls the [[StarfishAliens "Mother Thing"]].

Kip, Peewee, and the Mother Thing find themselves in Wormface and his fellow aliens' secret base on the moon and manage to escape, albeit briefly. After the failed attempt, the wormfaces decide to move the prisoners to an even more remote base on Pluto. There, the Mother Thing atempts an escape by setting up a beacon to contact her people, but seems to be fatally injured before she can activate the beacon. Kip completes the task and ends up almost dead himself. It turns out she was fine -- her species can just shut itself down in a way that simulates death.

Fortunately, they are rescued and treated by the Mother Thing's people. Unfortunately, the Mother Thing's people like to [[HumanityOnTrial judge new races]] to see if it's safe to let them join galactic society. Kip finds himself called upon to [[PleadingTheHumanCase defend humanity's right to exist]]... despite having just graduated from high school.

In what may be the quintessential Heinlein ending, [[spoiler: mankind wins the right to live, everyone gets home safe ''with'' scientific proof of their adventure, and Kip turns out to be a mathematical genius.]]

!!This novel provides examples of:

* AscendedFanboy: Kip yearns to go to space. He gets more space than he ever expected.
* AsimovsThreeKindsOfScienceFiction: A glowing example of "Adventure" science fiction -- boy gets space suit, goes on adventure fighting aliens -- but the [[TechnologyPorn detailed descriptions of Oscar]] in the first act verge on "Gadget" sci-fi.
* AndYouWereThere: Weird variation in the Full Cast Audio recorded book edition. When Kip holds imagined conversations with Oscar, the suit's replies are done by the same actor playing Kip's father.
* ArtisticLicenseHistory: Invoked in-universe. The alien court only very slowly realizes that their captured Neanderthal is not related to modern humanity.
** ScienceMarchesOn: ...while the modern genetic studies show that Neanderthals ''are'' related to us -- we've simply assimilated them.
* BadassBoast: Centurion Iunio, [[spoiler: on trial for humanity]] loses his temper.
--> '''Iunio''': I'll make a funeral pyre of you! I'll temper my blade in your guts! I who am about to die, will show you a Roman's grave-piled high with Caesar's enemies!
** Later in the trial, when things seem to be going badly, Kip angrily shouts that humans will ''make'' a new sun if the Earth is "Translated".
* BewareTheNiceOnes: The Mother Thing is gentle, soft spoken and eternally pleasant, with a small, frail looking body and enormous lemur like eyes. She also is fully capable of building a pair of bombs to destroy an alien base under her captors' noses and kill all of its personnel to guarantee her, Kip and Peewee's escape.
* BottledHeroicResolve: Dexedrine is your friend when you're trying to jog forty miles across the Lunar surface.
** Which brings up all kinds of ValuesDissonance, as no sane pharmacist nowadays would even dream selling amphetamines to a high-school kid, space-suit or not.
* BrattyHalfPint: Peewee. Not as bad as some examples, but she's got all the hallmarks.
* ChekhovsSkill: The first chapter is mainly about Kip's father encouraging him to study higher levels of math and science than what is taught at his high school. Most of this comes in handy later, like when Kip manages to prove that the base he is in is in fact on Pluto. He also studies both Latin and Spanish, and Iunio the Centurion whom he meets later speaks a hybrid of the two.[[note]]While [[{{RealityIsUnrealistic}}this may seem contrived]], it's {{TruthInTelevision}}, since Roman generals were often given land in the newer Roman province of Hispania.[[/note]]
* CompanionCube: Oscar, Madame Pompadour.
* CompetitionCouponMadness: Kip wins his spacesuit in this kind of competition.
* TheDeterminator: Kip, walking out into an impossibly cold Plutonian night to set the rescue beacon, slowly freezing to near-death in the process. Not to mention the Mother Thing, who didn't even bother wearing a spacesuit when she tried it.
* EveryoneCallsHimBarkeep: The Mother Thing. She just ''is''.
* ExplosiveLeash: Jock tells Kip that the Wormfaces implanted remote control bombs in the heads of him and his partner so they couldn't escape. He's probably lying, though.
* {{Farmboy}}: Before his adventure starts, Kip is your average kid getting ready to start college. He even works as a soda jerk at the local pharmacy (see {{Zeerust}} below). In fact, he's such an archetypal 1950s All-American boy that after he's done saving the Earth, he goes right back to work behind the soda fountain.
* FauxtasticVoyage: After Kip sets the beacon on Pluto and they're rescued by Mother Thing's people, he wakes up in a replica of his own bedroom constructed according to his memories.
* HumansAreSpecial: Averted. Humans are just another slightly troublesome race. Fortunately the Three Galaxies council decides to give them a chance rather than destroy them.
* HumanityOnTrial: Quite possibly the UrExample.
* ICallItVera: Oscar
* ImAHumanitarian: The Wormfaces
* InconvenientItch: While trekking across the lunar surface, Kip itches all over but can't scratch because of the space suit he's wearing.
* InsignificantLittleBluePlanet
* KnightInShiningArmor: Kip dreams of them and reflects on the trope more than once.
* LittleStowaway: Peewee
* MacGyvering: Kip deals with trying to charge Peewee's empty suit bottles, which have incompatible joints with his own by wrapping them together with [[DuctTapeForEverything duct tape]].
* NoOSHACompliance: Kip's spacesuit is a marvel of safety engineering, averting the trope. Peewee's cheap tourist model suit, on the other hand, plays the trope straight - any child that got lost on the Lunar surface would be doomed pretty quickly. ''No emergency radio?''
* PleadingTheHumanCase
* PsychicPowers: The Mother Thing communicates partially by song, partially by empathic projection.
* RewardedAsATraitorDeserves: Jock and Timothy, the Wormface's human minions, who betrayed the entire human race are eventually [[spoiler: turned into "Jock and Timothy soup"]].
* SciFiWritersHaveNoSenseOfScale: [[AvertedTrope Averted]]. It's ''Heinlein'', people. What did you expect?
** The book's "stages" actually help convey the colossal scale of events. Kip is transported to the Moon, and he marvels. Then he's imprisoned in an underground base on Pluto, and he goggles. ''Then'' he's rescued and taken to a planet near Sirius for emergency surgery, and he's dumbfounded. And finally he's transported to a different ''galaxy'' to be a witness at the Wormfaces' trial, and he muses that he's run out of astonishment.
* SecondPrize: The Spacesuit
* ShoutOut: The title refers to Series/HaveGunWillTravel.
* SmallUniverseAfterAll: The Three Galaxies government covers [[ExactlyWhatItSaysOnTheTin three galaxies]]: the Lesser and Greater Magellanic Clouds and the Milky Way. They have ships that can travel instantaneously between galaxies.
* SorryToInterrupt: While being held prisoner on the Moon, Kip enters Peewee's room and finds her crying. She doesn't notice him, so he sneaks out and then starts to head back while making a lot of noise so she can hear him coming and hide the fact that she was crying.
* SpaceIsCold: Averted.
* SpacesuitsAreSCUBAGear: The cover of the 1958 edition.
** Not unreasonable, as Kip's sporadic descriptions of the suit make it sound like a diving suit built to withstand vacuum. Though his planned improvements on the technology definitely avert this.
** He also tests it at one point by taking a stroll through a lake.
* SpeciesLoyalty: Kip and Peewee wish to return to Earth regardless of the ruling.
* StarfishAliens
* StarfishLanguage: The Mother Thing sings when she speaks, and only the person she is speaking to can understand what she's saying.
* WouldBeRudeToSayGenocide: Races that have troubled the Three Galaxies have their worlds "Translated" to another point in space.
-->'''Kip:''' "That doesn't sound so bad."
-->'''Mother Thing:''' "...they don't take their sun with them."
* YouHaveOutlivedYourUsefulness: Jock and Timothy, the Wormface's human minions.
* {{Zeerust}}: Navigating the stars... with a slide rule. As in many of Heinlein's juveniles, the setting is a strange (to modern readers) ultramodern version of the 1950s -- live prime time TV and soda fountains in drugstores coexist with orbital space stations and interplanetary flight. [[note]]Slide rules are practically Heinlein's calling card. It'd probably be faster to list the books of his that don't have "slide rule" or "slip stick" mentioned somewhere. He used the term "slipstick" so regularly, whole generations of his fans are growing up with the erroneous notion that people who used slide rules on a daily basis actually ''called'' them that.[[/note]]