He's not alone in his troubles, either; he gets help (well, sort of) from inspector Lispington of the Scotland Yard and his beloved and clever dachshund Tickie. Together, they never fail to save the day and thwart the plans of any counterfeiters, jewel thieves, embezzlers and other criminal elements that haunt the world.
This book series provides examples of:
- Acrofatic: Despite his rotund shape, Agaton Sax is a master of jiu-jitsu.
- Always Murder: This series inverts the trope. Since it's a children's series, there are no murders, or even suspected cases of murder.
- Contrived Coincidence: The plot of the Swedish edition of Agaton Sax and the Big Rig is dependent on Agaton Sax happening to find himself close to the home of one of the world's very few other speakers of Cryptic, an extremely obscure language spoken by less than a hundred people world-wide. The plot is also dependent on Agaton happening to know that this is where said person lives, which is even less likely—for instance, how many real-life language students would know the address of Noam Chomsky?
- Criminal Doppelgänger:
- Agaton Sax and the Criminal Doubles features two men who both resemble some famous criminal and enemy of Agaton Sax. One of them is a perfect copy of Julius Mosca, and the other resembles Octopus Scott exactly. Because of this, they get arrested every day, and have started to demand (and receive) compensation payments from the government, which are paid out to them each time they get arrested.
- Agaton Sax and the Diamon Thieves features a criminal double of Agaton Sax himself.
- Inspector Oblivious: Officer Lispington of the Scotland Yard is such an effective policeman that he sometimes doesn't accidentally make things harder for Agaton Sax. Only in the books where he appears. One prominent example is in Agaton Sax and the Diamond Thieves, where he frequently thinks the doppelganger is the real Agatn Sax and vice versa.
- Legion of Doom: Agaton Sax and the Criminal Doubles sees several of the previous villains of the series teaming up.
- Mystery Magnet: Agaton Sax very often finds himself embroiled in some sort of mystery-solving or hunted by criminals.
- Omniglot: It would be impossible to provide a list of all the languages Agaton Sax speaks, since there's no room for such a large list. It would also be impossible to provide a list of all the languages that he doesn't speak, since that would require us to find at least one such language.
- Ruritania: The countries of Brosnia and Mercegovina are stereotypical eastern European countries. Their names are based specifically on Bosnia and Hercegovina, which were still two different countries when the books were written, while the actual countries are more generic.
- "Scooby-Doo" Hoax: Agaton Sax and the Haunted House features a haunted house that quickly turns out to be an elaborate fake.
- Shown Their Work: At one point in the Swedish edition of Agaton Sax and the Big Rig, Agaton Sax is hanging from a bridge in Scotland. The narration tells us a whole lot of technical data about the bridge, none of which is plot-relevant, before moving on with the story.
- Translation: "Yes": The two languages Cryptic and Brosnian represent the two versions of this trope, the former using just a few words to say a whole lot and the latter using very many words to say things like "Yes."
- You Just Ruined the Shot: In Agaton Sax And the Scotland Yard Mystery the titular Agaton Sax is on board an old-fashioned ship, which—apart from Agaton Sax and the captain—is crewed completely by disguised criminals. But out of nowhere, a pirate ship appears and fires (a blank from) the cannon, and its crew boards the first ship. Very soon, it turns out that the "pirate ship" is actually part of a movie, and the "crew" is a bunch of actors who mistook Agaton Sax's ship for another ship that they were supposed to fight as part of the movie.