This contains examples of the following tropes:
- Art Evolution/Art Shift: The series changed artists around "Sam Samurai", and the art style becomes markedly different, switching from overexaggerated cut-out styled near-abstractions, to moderately exaggerated, clean-cut cartoon characters.
- A Little Something We Call "Rock and Roll": "Tut, Tut" has the boys introduce basketball to the eponymous character.
- "See You Later, Gladiator" has the boys introduce professional wrestling to the Romans, as an alternative to having to stab and kill a fellow slave.
- Because Destiny Says So: In "See You Later, Gladiator", the Vestial Virgins spare Sam, Joe, and Fred, as well as allow them enough time to get back home. When one of the boys ask why, one of the Virgins pulls out a prediction that details the boys' entire trip to Rome.
- Can't Take Anything with You: In one book, the boys decide to go back to cavemen days with a bunch of modern technology to change the future. The Book doesn't like that, and not only refuses to bring their stuff, it leaves behind their clothes, save for Sam's Nerd Glasses and Fred's baseball cap. (Joe got to a keep a straw he was using for a magic trick.)
- Evil Chancellor: Used a few times, often to add tension to the boys' interactions with real historical figures (or make those historical figures more sympathetic by comparison). Hatsnat and Bull Bear stand out.
- Family-Unfriendly Death: Would have happened to the boys in "Tut, Tut" - the main villain turns them into living-but-not-prepared-for-embalming mummies and triggers a trap door that sends several tons of rocks completely encasing the room the boys are in, trapping them in the sarcophaguses. If the rocks didn't crush them and they didn't die of starvation and dehydration, they'd die of asphyxiation. Fortunately, one of the boys' nieces has a cat that finds the book in the rubble...
- "See You Later, Gladiator" has the boys avert this. Normally, their fight with their companion should end in death - but they then introduce professional wrestling (not pankration, professional wrestling) to the Romans.
- Once more averted in "Sam Samurai". For insulting a samurai, they would have been executed on the spot, had it not been for their granddaughters. Yes, insulting a samurai was a grave insult that usually resulted in death for peasants.
- First-Person Perspective: The books are always told from Joe's perspective.
- Gladiator Games: The entire point of "See You Later, Gladiator".
- Historical Hero Upgrade: Thoroughly averted in The Good, the Bad, and the Goofy, with respect to Lt. George Custer. He's not especially demonized, either, but the boys fall in with Black Kettle partway through the book, and it's pretty clear who the reader is meant to sympathize with. (At the beginning of the book, before the timey-wimey stuff starts, the boys are watching a Western TV show that plays this trope dead straight; Sam has a few things to say about that.)
- I Shall Taunt You: Fred employs this against the Black Knight in Knights of the Kitchen Table, reasoning that trying to spear them while wearing tons of armour will wear him out. He's right.
- Is the Answer to This Question "Yes"?: At the end of "It's All Greek to Me", one of the boys asks Apollo, the god of music, if he can play anything but "Twinkle, Twinkle, Little Star".Apollo stared at us as if we'd just grown another head."Can I play music? Is Aphrodite beautiful? Is Athena smart? Can Dionysus drink wine? Give me that stringed thing; I'll show you music."
- Let's Split Up, Gang: Done in "Tut, Tut." Fred protests, citing films where this leads to the characters getting "bumped off", but their Egyptian helper is merely confused.
- Made a Slave: The boys in "See You Later, Gladiator", as well as their guide, who they try to help win freedom.
- Mr. Exposition: Actually justified in-universe: the book has a "guide" option that not only turns normally hostile people into, well, guides for whoever uses it, but will also help them point out features of the era and install a Weirdness Censor, so people don't ask why there are three kids in the most bizarre clothing running about in foreign countries. It saves their life a few times, as their "guides" included a samurai who was about to slice off their heads for trespassing.
- One Steve Limit: The Tut in "Tut, Tut" isn't Tutankhamun. It's lampshaded.
- Ridiculous Future Inflation: In "2095" a slice of pizza is worth well over a hundred dollars.
- Samurai: The point of, well, "Sam Samurai".
- Uncanny Family Resemblance: Jo, Freddi, and Samantha look exactly like their great-great-grandfathers, except with longer hair.
- Unfortunate Names: Once a book. Hatsnat (pronounced "Hot Snot"), Owattabatt (pronounced "Oh, what a butt"), and so on. Each time, it usually gets the boys nearly killed or in trouble. For example, they are discovered eavesdropping on Hatsnat's plans to become great and powerful by trying not to laugh at his name, and are nearly executed by Owattabatt (a samurai) for bursting into laughter at his name.
- A helpful servant of the Emperor in "Sam Samurai" is literally named "Silly Elephant" in Japanese. The samurai that guides around the boys is befuddled.
- In one of the later books, this actually gets a Lampshade Hanging— "We always run into villains and they always seem to have terrible names."
- Volleying Insults: With Hatsnat. Made funnier by the fact that the priest is taking the situation seriously (and is clearly on the verge of blowing a fuse), while the boys...are not."We are magicians, Hot Slop."
"Minions of Set!"
- Weirdness Censor: The book comes with this - it not only works a Universal Translator, but it also assigns random people in the era to become friendly (when they were trying to kill them mere moments ago) and show them the land without questioning the weird garments or pale skinned foreigners.
- We Will All Fly in the Future: In "2095", personal anti-gravity discs the size of large lapel pins are commonplace, and worth only a few cents (when a slice of pizza is over a hundred dollars).
- Word-Salad Humor: When Owattabatt is about to execute the boys in "Sam Samurai", his deadly threat is as such: "Now you will bark bark meow meow oink oink." It's justified in-universe: the time-travelling book has language options that automatically translate for the travelers, and the book decided to go on the fritz.