[[caption-width-right:350: Everyone, [[ActingUnnatural act natural]]![[note]]From L to R: [[OnlySaneMan Gero]][[ButtMonkey nimo]], [[TheBigGuy Tr]][[CloudCuckooLander ap]], [[TheLancer Th]][[BreakoutCharacter ea]], [[TheSmartGuy Benj]][[TagAlongKid amin]].[[/note]]]]

'''''Geronimo Stilton''''' is a children's book series originally written and published in UsefulNotes/{{Italy}} that stars the titular hero, Geronimo Stilton, a mild-mannered but brave mouse who works as a [[FlintstoneTheming famouse]] journalist for the Rodent's Gazette, the most popular newspaper in New Mouse City.

He goes on several kinds of adventures, ranging from catching master thieves to searching for sunken treasure to racing across America to participating in cooking competitions. He is often accompanied by his sassy sister Thea, his boorish cousin Trap, and his favorite nephew Benjamin.

All of the books are written by Geronimo in first person, detailing all of his thoughts and experiences about the crazy things that come to his doorstep.

The books have been successful enough to spawn several SpinOff series:

* '''''The Thea Stilton Series'''''. Thea becomes a journalism instructor at Mouseford Academy. While Thea is the title character, the books actually focus on a group of her prize students, "The Thea Sisters". Five girls from around the world, the Sisters become not only FireForgedFriends, but a MultinationalTeam of {{Amateur Sleuth}}s. This spinoff itself has a spinoff in form of graphic novels, for a higher reading level.
* '''''The Creepella von Cacklefur Series'''''. Creepella, Geronimo's [[Creator/ElviraMistressOfTheDark Elvira]]-like friend/[[AbhorrentAdmirer abhorrent admirer]], is a VegetarianVampire who lives in a HauntedCastle with her [[Series/TheAddamsFamily Addams]][=/=][[Series/TheMunsters Munsters]]-style relatives. [[TheyFightCrime They solve mysteries.]]
* '''''The Cavemice Series'''''. These prehistoric tales star Geronimo Stiltonoot, editor of Old Mouse City's ''Stone Gazette'', and other {{Identical Ancestor}}s of the main cast. They live in a ''WesternAnimation/{{Flintstones}}''-like world where dinosaurs (some of which talk) provide transportation, and the threats include frequent natural disasters as well as Tiger Khan and his marauding horde, The Saber-Toothed Squad.
* '''''The Spacemice Series'''''. These books are set in a ParallelUniverse where Captain Geronimo Stiltonix and the crew of the [=MouseStar=] 1 explore the universe and interact with aliens. Expect plenty of SpaceOpera tropes.

The original book series has been adapted into an [[AnimatedAdaptation animated series]] as a joint venture by Italy, Canada and other countries; first aired in Italy (Italian) and Canada (English), and shown in several other countries shortly after. As of writing, a 3rd season (almost nothing is known about it) is in production. Despite being based on the books, the show is about 98% original material.
!!Geronimo's literary adventures include examples of:
* AbhorrentAdmirer: Creepella Von Cacklefur to Geronimo.
* ActuallyIAmHim: When Geronimo first met his newly-hired assistant, Pinky Pick, he assumed she was his assistant's daughter, since she's only fourteen years old.
* ArsonMurderAndJaywalking: Chef Stewrat's long and very disgusting list of ingredients for his stew recipe ends with "...[plus] a little salt and pepper!"
* ArtEvolution: In the first books, Trap looks different, wearing a white shirt and red suspenders. Later he gets his current look, with the ponytail, earrring and Hawaiian shirt. [[OrwellianRetcon some reprints of older books redraw him with the current look]].
** Also, the poltergeist that lives in the Cacklefurs' castle is just a BedsheetGhost in his first appearance. He gets mouse features in the spinoff series.
* BarefootCartoonAnimal: Despite being otherwise fully-dressed, almost none of the characters wear shoes. The most notable aversion is [[TheOneWhoWearsShoes Pinky Pick]], and ''[[NiceShoes how]]!'' Although the Thea Sisters start this way, in the later books they (and most of the other characters) wear shoes more often than not.
* BigfootSasquatchAndYeti: In "I'm Too Fond of my Fur!"
* BigShadowLittleCreature: This happened with Benjamin (Geronimo's nephew) in one book.
* BlindWithoutEm: Geronimo. In the show, however, he doesn't wear glasses.
* BondJamesBond: "My Name is Stilton, Geronimo Stilton!"
* CatchPhrase: Shif T. Paws in ''Watch Your Whiskers, Stilton!''.
-->'''Shif T. Paws:''' [[TitleDrop Watch your whiskers]], here comes Shif T. Paws!
* CatsAreMean: The titular pirates in ''Attack of the Bandit Cats'' and the Saber-Toothed Squad from the ''Cavemice'' books.
* ChasteToons: Benjamin is Geronimo's favorite (and only) nephew. A rather extreme example, as Geronimo's only mentioned sister, Thea, is not Benjamin's mother, nor is any mention of her made in any of the books (yet). All this despite there being [[LoadsAndLoadsOfCharacters Loads and Loads of Stiltons]].
* CoolCar: ''Get Into Gear, Stilton!'' has two of them: Solar, a talking, robotic car with ArtificialIntelligence, and its [[EvilTwin evil equivalent]] Lunar. Geronimo is the only driver Solar will accept, which isn't surprising once it's revealed that [[spoiler:Solar's voice and personality are modeled after Thea]].
* CutLexLuthorACheck: Glauseter the video game company owner steals an idea for a video game called ''Ratzilla'' from a little boy named Chas, and commits numerous crimes in order to keep people from knowing the game was Chas' idea - including wiping their memories with an amnesia machine. Why doesn't he make money off of ''that'' and not some ''Godzilla'' ripoff game?
* CreepyGood: Creepella.
* DarkIsNotEvil: The Cacklefurs.
* DeathTrap: In "Watch Your Whiskers, Stilton!", the game show "The Mousetrap" centers around a gigantic bladed mousetrap that the contestant is chained to.
* DisguisedInDrag: In ''Paws Off, Cheddarface!'' Trap is made up to look like Sally Ratmousen in order to counter her IdenticalStranger Gambit.
* TheDoorSlamsYou: Happens to Geronimo a number of times in "Watch Your Whiskers, Stilton!"
* EvenEvilHasStandards: In ''The Giant Diamond Robbery'', Sally Ratmousen's profile states, "She's known for breaking the rules, except on the golf course, because that's unethical!"
* FunnyAnimal[=/=]WorldOfFunnyAnimals
* HoldYourHippogriffs: The books are stuffed with [[FlintstoneTheming mouse-ified phrases]].
* HurricaneOfPuns: Mouse puns, mostly.
* IdenticalStranger: ''Paws Off, Cheddarface!''
* JerkAss: Trap. ''And how''.
** Sally Ratmousen would be the biggest example.
* LiteraryAgentHypothesis: All the books in the main series are "written by" Geronimo himself. The ''Cavemice'' books were written by Geronimo's prehistoric ancestor and translated by present day Geronimo. The ''Thea Sisters'' books start with Thea learning about the Sisters' latest adventure, then (supposedly) recounting it.
* NiceMice: Both played straight and {{averted}}; almost all the characters, good or bad, are mice.
* NotAllowedToGrowUp: You'd think that after all the adventures the gang goes through, they're portrayed as being older.
* TheOneWhoWearsShoes: Pinky Pick.
* OnlyKnownByTheirNickname: Inverted. Many side characters are referred by name, surname and nickname.
* PlotDrivenBreakdown: In "A Very Merry Christmas," Geronimo accidentally picks up someone else's bag instead of his own. The other person calls her own cellphone and starts to make arrangements for her and Geronimo to meet up and exchange bags, but her phone dies ''just'' before she says where to find her.
* PunctuatedForEmphasis: Some lines in the books are irregular and in color to emphasis the characters' thoughts.
* SceneryPorn: Later books have BEAUTIFUL backgrounds. Most notably is the Fantasy Kingdom books (The third one has a beautiful depiction of New Mouse City in spring)
* SequelHook: Some books end with Geronimo talking about something that happened after the end, saying "But that's another story, which I'll tell you very soon!". None of these sequels happened yet[[note]]including a ''Paws Off, Cheddarface!'' sequel where Geronimo exploits the IdenticalStranger for his own needs and one about Geronimo running at the New York Marathon[[/note]].
** A particular case was the [[VerySpecialEpisode Oliver]] story. It was a short book about one of Benjamin's schoolmates, the titular [[LongLostUncleAesop Oliver]], having problems to move around with his wheelchair. With the help of his friends and Geronimo, he gets the mayor of New Mouse City build more entry ramps in the city, and the story ends with a [[TwentyMinutesIntoTheFuture scene from ten years later]] where an adult Oliver wins at the Special Olympic Games, with Geronimo's "I'll tell you very soon!" speech, and a advertisement promising a full series starring Oliver and dealing with a different disability in each book. Both of these things never got released, sadly.
* ShaggyDogStory: "Geronimo Stilton, Secret Agent"
* ShoutOut: In "The Secret of Cacklefur Castle," the Cacklefurs have a pet cockroach named [[Creator/FranzKafka Kafka]], a reference to Literature/TheMetamorphosis.
* SpeciesSurname: Not as many as you'd think.

!!The Animated Adaptation include examples of:
* AbhorrentAdmirer: Geronimo gets another one in the form of the Contessa in the S2 episode "Bloodlines".
** Thea has one in a few villains, notably Prince Nogouda who repeatedly attempts to force her to marry him.
* BadBoss: Sally to Simon. Even when he performs well, she berates, mistreats and insults him.
* BarefootCartoonAnimal: Just as in the original books. However, as a variation, they do put on the needed footwear once they venture out of civilization.
* BigfootSasquatchAndYeti: Big Toes, from the S2 episode "The Legend Of Big Toes". [[spoiler: Though he's actually no different from the humanoid mice in the show; only much, much taller, hairier, and being [[TheSpeechless speechless]].]]
* BrokenPedestal: If someone is introduced as being an old friend or former mentor of Geronimo's, they have a rather disturbing tendency to turn out to be a villain. Poor Geronimo has seen more of his former heroes turn out to be complete bastards than a lot of other protagonists.
* ButtMonkey: Trap is more of this than his cousin Geronimo was in the original books.
** Simon Squealer is this, too.
** And of course, Geronimo himself.
* CompositeCharacter: Benjamin in the TV series appears to be given the role and personality of his counterpart in the book series and Pinky Pick.
* ChekhovsGun: At the beginning of "The Mask of Rat-Jitsu", Geronimo takes out a vial of a rare, strong-smelling cheese from his safe and inadvertently puts it in his clothes. He finally got to use it [[spoiler:during the said episode's climax to knock out the villain of the episode and his {{mook}}s.]]
* TheChessmaster: Crunchrat is prone to be this way.
* CrouchingMoronHiddenBadass: Geronimo can sometimes be capable of overcoming his clumsiness and apparent cowardice when the chips are really down, and Trap has his moments, too. Most notable of all is Simon Squealer, MinionWithAnFInEvil extraordinaire, who, while usually a clumsy and incompetent SmugSnake, is shown to possess martial arts skills that make him an even match for Thea!
* DisguisedInDrag: Simon... and he's surprisingly attractive as a redheaded.
* EverybodyLaughsEnding: Done for a few episodes.
* EverythingIsOnline: The only explanation on how Benjamin could hack into almost anything.
* EvilTwin: Geronimo deals with one in ''Paws Off, Cheddarface''.
* [[FiveManBand Five Mouse Band]]: The main characters are presented as this:
** TheHero:Geronimo
** TheLancer: Thea
** TheBigGuy: Trap
** TheSmartGuy: Benjamin
** TheChick[=/=]TagAlongKid: Pandora (Bugsy Wugsy in the books)
* TheFool: Trap. Full stop.
* GoodFeelsGood: Simon comes to this realization when he impersonates a superhero and rescues Thea from drowning. Unfortunately for him, it only leads to a HeelFaceDoorSlam.
* HollywoodHacking: Benjamin does this ''in spades''.
* HurricaneOfPuns: Expect a ''lot'' of rodent and cheese puns. Some of them might be funny.
* HypnoFool: Geronimo becomes one in "Hypno Tick Tock", courtesy of an evil hypnotist who plans to MindControl the entire city.
* InevitableWaterfall: In the S2 episode "The Legend Of Big Toes", Geronimo was tricked into falling into the river and almost fell down one of these. [[spoiler: He was saved by the titular Big Toes.]]
* TheLabRat: Literally in [[TheProfessor Professor]] [[GadgeteerGenius Von Volt's]] case.
* TheOneWhoWearsShoes: Sally Rasmaussen wears a pair of killer heels.
** When she's kidnapped by the titular gangster in "Barry the Moustache", Geronimo and company find a clue when she [[LosingAShoeInTheStruggle loses a shoe in the struggle]].
* RedHerring: Although the show is usually pretty straightforward with who the villain is, there have been a few exceptions where the character everyone suspects is innocent:
** One episode had tomb-robbing in Egypt. Everyone suspected it to be the work of a kindly professor's shifty nephew with a DarkAndTroubledPast who nobody trusted. [[spoiler: It is eventually revealed it was his seemingly benevolent uncle and not him all along.]]
** Another episode had Benjamin and Pandora visiting a cheese factory owned by Chauncey, when someone steals the only sample of a new kind of cheese. When it is learned one of the other kids in the tour is [[spoiler:the son of a rival factory owner]], everyone suspects him. [[spoiler:But it is eventually revealed to be Chauncey's assistant, who wanted revenge on his boss because Chauncey only paid him in cheese.]]
** Geronimo and the gang went on a fashion shoot tour with a pair of hip (and strange) European fashion photographers, and everywhere they went, someone was robbed. Local police arrested Thea for it, and it seems as though the photographers are the real thieves who are just using the shoot as a cover for their crimes, [[spoiler:but it eventually turns out to be the shoot's makeup artist, with the photographers entirely innocent and the shoot genuine]].
* ReusedCharacterDesign: The show has a few examples of this, but the most prominent are the two (or three?) large {{Mooks}} in black business suits. They're first used as Prince Nogouda's bodyguards, but later turn up in a variety of roles, either as private security (for good guys) or henchmen (for bad guys). Basically any time the episode calls for one or more big, tough-looking mice, these guys get drafted. In their most recent appearances, they've been doing muscle work for Sally. Either the animators are just really lazy... or [[WildMassGuessing it really is the same two or three guys]] [[EpilepticTrees working different jobs each time]].
* SavvyGuyEnergeticGirl: Geronimo and Thea.
* SayMyName: "Crunchrat!"
* TerrifiedOfGerms: Prince Nogouda.
* TookALevelInBadass: While still somewhat a NervousWreck, Geronimo is noticeably braver than in the books.
* TookALevelInKindness and TookALevelInDumbass: Trap is more well-meaning here, but he is also less bright.
* YouGottaHaveBlueHair: Chauncey the cheese factory owner and [[Literature/CharlieAndTheChocolateFactory Willy Wonka]] {{Expy}} has purple hair for... some reason.