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Charlie Thorne #4

Charlie Thorne and the Royal Society

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In the fourth installment of the New York Times bestselling Charlie Thorne series—which #1 New York Times bestselling author Chris Grabenstein called “a real page-burner”—Charlie searches for Isaac Newton's secret treasure across Europe and Australia.

Charlie Thorne is a genius. Charlie Thorne is fearless. Charlie Thorne may have finally met her match.

Charlie Thorne is used to being on the run. Ever since she was recruited by the CIA to track down Einstein’s most dangerous equation, Charlie—and former CIA agents Dante Garcia and Milana Moon—have traveled around the world to prevent history’s greatest discoveries from falling into the wrong hands. But after beating others to the secrets hidden by Einstein, Darwin, and Cleopatra, they find they are not the only ones searching for an immensely powerful discovery of Isaac Newton’s.

From a chase over the rooftops of Cambridge University to scaling the Sydney Harbour Bridge to skirting a volcanic eruption, Charlie will need to think one step ahead of her opponents to follow Newton’s trail of devious clues and keep herself out of the hands of the many enemies who are hot on her tail.

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First published January 1, 2024

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Stuart Gibbs

92 books3,662 followers

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5 stars
880 (55%)
4 stars
529 (33%)
3 stars
146 (9%)
2 stars
16 (1%)
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4 (<1%)
Displaying 1 - 30 of 121 reviews
Profile Image for Brok3n.
1,451 reviews114 followers
July 25, 2025
Fun, but I didn't believe it

We knew from the ending of Charlie Thorne and the Curse of Cleopatra that the next historic secret Charlie would chase after would be something discovered by Isaac Newton. In fact, as the title suggests, it is broader than that. This one involves not just Newton, but many of his colleagues and fellow members of the Royal Society of London. In fact, at 413 kindle pages, this is the longest Charlie Thorne installment so far, and that is partly because in addition to Newton, we end up chasing the history of several of his contemporary Fellows of the Royal Society.

Although I really have no information about Stuart Gibbs's creative process other than that revealed by the end matter in his books, I have long suspected that he writes his novels backward -- that is, that he imagines the end first, and then writes the earlier sections in order to move his people and pieces to the place where that ending can transpire. For what it's worth, he begins the Notes and Acknowledgments with which this novel ends by describing what inspired it, and that inspiration is about the final scenes of the book.

So, when I read a Stuart Gibbs novel I expect the final scene to be the best -- the purpose towards which everything that came before was working. And this time, I am sorry to say, I found the final scene disappointing. I didn't believe it. Let me state right up front that, yes, I am clear on the concept of fiction. You're not *supposed* to believe a story like this -- you know it's just a tale. But at some level, you do need to believe as you read. That's why we talk about suspension of disbelief. It's a collaboration between the author and the reader. And this one just didn't work for me.

Why? Well, partly it was because the secret was just too much of a stretch. He addresses that as follows
And while I’m at it, the idea that we might be able to ... isn’t as far-fetched as you might think. There are a good number of respected scientists who believe that it’s possible.
I am, as it happens, familiar with the research he alludes to here, and nevertheless the story as told here just felt too far-fetched.

Besides that, there were a couple of other things that bothered me. For one, early on Charlie gets herself into trouble by behaving foolishly. I know you need to get your hero into some kind of trouble to have a plot, but to do it by having your super-intelligent hypercompetent hero act like an idiot undermines the entire premise of the series.

Also, Gibbs has an unfortunate tendency at times to be sloppy about facts. I think the first time I really noticed this was in Spy School Revolution, when Ben claims to have read the story of the Trojan Horse in The Iliad -- the story of the Trojan Horse in fact appears nowhere in The Iliad. This made nonsense of a major plot point. Charlie Thorne and the Royal Society is marred by a number of smaller factual errors. I'm not going to list them here, but I have noted some of them in my kindle notes, which Goodreads users can look at, if they care.

So, overall it was fun, and I have no doubt Gibbs's devoted fans will give him all the stars. I cannot.

Blog review.
Profile Image for Beth Menendez.
428 reviews25 followers
May 10, 2024
I love Charlie Thorne adventures. What a fantastic middle grade read. If you haven’t discovered this series, you are in for a treat this summer!
Profile Image for Donna.
75 reviews5 followers
March 5, 2025
This series is so smart and witty and I was extremely sad to finish this installment. I really hope there is another one on the way!!
Profile Image for Holly Huston.
40 reviews
May 1, 2024
An amazing book! I loved it so much! Couldn’t put it down!
5 reviews
July 31, 2025
very interesting, and action packed all the way. great ending, cleverly written.
Profile Image for Dilynn Walters.
67 reviews1 follower
May 14, 2024
I’m a big fan of Stuart Gibbs books, and so I was really excited to hear about a fourth Charlie Thorne. I read this book right after it came out, hoping for a story as satisfying and exhilarating as the previous three. I didn’t dislike this book, but it didn’t strike my interests quite as much as the first and third ones.

One the one hand, this book does a great job of capturing the setting and feeling of all the places they travel to. It was fun to be in London, Australia, and Hawaii, all in this book!

A thing I didn’t like though, was how parts of the book would just be pages and pages of facts, before going into the actual story. It was interesting to learn, but got kind of old after a while.

I also would have liked to see more of Milana Moon. She‘s a strong and important character, that I feel could’ve been mentioned more, or had a bigger role.

The plot felt really intriguing, and had the familiar action scenes that I enjoyed, up until the end. And I don’t want to spoil anything, but let’s just say that the ending felt pretty far-fetched and mediocre after the story led up to it for almost 400 pages.

But… overall, I loved getting to meet up with Charlie, Dante, and Milana, along with some new bad guys and more intense of a storyline!

✨4/5✨ Stars because I expected a bit more but still liked reading “Charlie Thorne and the Royal Society” a lot!
Profile Image for Ms. Yingling.
3,923 reviews605 followers
June 3, 2024
Copy provided by Young Adult Books Central

Once again, Charlie is on the run. Her half brother, Dante, and former agent Milana Moon are also trying to fly beneath the radar, so setting up fake passports. It's not cheap, but then, after Charlie's hacking adventures, she can afford it. This money also allows her to occasionally travel without even needing a passport, but it's always good to have a backup. Unfortunately, too much information is out there about Charlie, some of it because of an unscrupulous analyst. Charlie is following the clues to another puzzle from Einstein's notes, and has traveled to Cambridge, England to follow up on "To find Newton's discovery, turn the tables in the Wren". While in the Wren Library, she runs into a student, Kenji, who is rather cute. Against Dante's advice, she asks him for help with the puzzle. Of course, this goes badly wrong when he takes the next clue and turns out to be the son of Yoshi Yataro, a billionaire also wanting Newton's secrets. Charlie embarks on another odyssey that takes her to London, Germany, Australia, Zion National Park, and eventually Kona, Hawaii, and causes her to find out a lot about the explorer James Cook and his troubled legacy. While I'm not entirely sold on the plausibility of the ending, it is spectacular.

Like the other three books in the series, this has several elements that make it an exciting and intriguing choice for middle grade readers. There are a lot of number and word puzzles to be calculated if one likes to do this (I do NOT!), international travel to so many different places, and a clever and intrepid character who is flying in the face of the establishment to solve riddles that only her training and intellect can crack.

It wouldn't be a Gibbs' book without a healthy does of humor, and Charlie is able to not only fight villains, but to enjoy the puzzles and travels while she does it. Again, the ending is a bit hard to believe, but does pack a snarky punch to it.

While Charlie isn't exactly a spy, her exploits are perfect for readers who enjoy tales of espionage and intrigue like Horowitz's Alex Rider books, Ponti's City Spies, Yee and Santant's The Misfits, Maxc's Swift and Hawk, McGee's Ryan Quinn, Hale's School for S.P.I.E.S., or Bradley's Double Vision series.
Profile Image for Ava.
23 reviews
May 22, 2024
Man I could NOT have expected the ending, still amazing as all the other Charlie books
Profile Image for Hedwig.
11 reviews
April 11, 2025
I thoroughly enjoyed reading this detailed, adventurous book—it felt as though I was part of the story. I highly recommend it to anyone looking for a thrilling journey filled with exciting adventures."

Profile Image for Riah.
366 reviews
October 9, 2024
This was a great read. We have read all the Charlie Thorne series as a family and this one definitely has the coolest ending. I, as the obligatory adult, was on pins and needles without any clue how this adventure was going to go. We are all hopeful for another in the series, and will likely never forget this one. What an adventure!
Profile Image for Anne.
798 reviews5 followers
May 7, 2024
Fun, exciting, AND educational. A great series for kids and adults.
688 reviews
February 7, 2025
I love this series and all of Stuart’s books. I own all except most of the spy school series and after finishing this book today will probably jump back into that series so I can have his stories in my brain more. I love seeing how Charlie is growing up and the fanciful world Stuart has created.
Profile Image for Eve Nicholson.
Author 3 books17 followers
March 13, 2025
I am so sad to have finished this series. IT’S TOO GOOD TO END! Although, I have to admit I was very pleased with the ending. I adore Charlie and her brother. I’ve loved their adventures.
Profile Image for Becky B.
9,330 reviews183 followers
September 25, 2024
Charlie Thorne, her brother, and his CIA partner are on the trail of Newton's secret discovery. But the CIA is hot on their trail and a Japanese billionaire also has Newton's secret in his sights, so they are not alone as they end their sea voyage in England and follow another string of clues around the globe to discover a secret discovery long-hidden from the world.

This adventure takes readers from England to Australia to Hawaii and the US Southwest. The CIA is breathing down their necks, and this Japanese businessmen has an eager-to-please grandson plus a lot of money to hire many others to get what he wants. It's quite the action-packed globe-trotting adventure and readers get to learn a lot of true things about Newton and Captain Cook along with other historical figures while they go on their slightly fantastical mission. Charlie and her brother also work some things out about their relationship and how they could do things better. A very enjoyable romp with the super smart Charlie Thorne.

Notes on content:
Language: None
Sexual content: None
Violence: There are a couple skirmishes and some bumps, scratches, and possible broken limbs are incurred. One fight results in 2 people dying in lava off page. A couple people are knocked out (mostly nonviolently).
Ethnic diversity: Charlie is multiracial as is her brother. There are other characters from all over the world with a variety of ethnicities.
LGBTQ+ content: I believe a male side character mentioned having a husband, but I might be mixing this story up with another one.
Other: Charlie and gang have to steal something to prevent the bad guys from getting their hands on it. The director of the CIA is manipulating things for his own greed. Charlie has to make a big decision at the end of the book related to .

Profile Image for Charisse.
140 reviews
July 25, 2024
Yay!!! I love this book obv.

I get what the other reviews say by "a little far stretched" and "not very believable" but I don't care, I love the books and nothing will ever change that.

There were some moments when I was scared about the story, but I know that Stuart Gibbs doesn't write like that, so I wasn't too worried. (I was absolutely panicking even if I knew it was going to be alright)
116 reviews1 follower
November 3, 2025
Really good book! I thought this was a good ending to the series. I love the characters, and thought the mystery was good. I wish Milana was in all of the book though. I loved the setting and it was really entertaining.
Profile Image for ang.
100 reviews2 followers
January 1, 2025
4.7 ⭐️ never disappoints
Profile Image for R.J. Shea.
8 reviews
June 29, 2024
Definitely my favorite book in the series! Lots is action and never expected the ending!
697 reviews1 follower
October 8, 2025
As usual, I enjoyed the history and the action. Love how Gibbs weaves the history into the action without it seeming boring.
I didn’t like the ending though. Too predictable. And too sappy.
40 reviews1 follower
June 26, 2024
He's done it again! Another great book by Gibbs. I can't wait for the next one.
Profile Image for Elliott L..
10 reviews
May 16, 2024
One of my favorite aspects of the Charlie Thorne series is that when you read the books you also learn so much about the history surrounding the plot. It was super fun to learn all about Isaac Newton and James Cook, and it didn't even feel like I was having to sludge through a history book about them. I really enjoy reading about all of the creative puzzles that each historical figure leaves. Charlie is also a great main character, and I enjoy her spunkiness.

The Charlie Thorne series, and this book in particular, has some deeper themes than other books by Stuart Gibbs, so I would recommend this book to readers who are 12+.
230 reviews
May 22, 2025
What a great ending! Salvation for those who enjoy a mix of philosophy and adventure! There is a possibility for a sequel series here. Charlie Thorne is a strong, resourceful and smart main character who just leads the plot really well.
Profile Image for Benson.
12 reviews
March 2, 2025
Great book, amazing read, I have read every Stuart Gibbs book and even sent him a letter (he replied) I think his books just keep getting better and better. What I liked most about this one is the blend of the James Bond-y mission and the history of these famous thinkers like Newtown and Cleopatra and Einstein. I've learned a lot from Stuart Gibbs' books whether it's learning about animals from funjungle to history in Charlie Thorn, Stuart Gibbs is one of my favorite authors and I really appreciate that he supports helping fix climate change and raise awareness for endangered animals. I would highly recommend pretty much any of his books.
1 review
January 14, 2025
One of my favorite books i have ever read

I liked this series a lot and i think that you should write another Charlie Thorne book that would be great.
2 reviews
October 22, 2024
I gave this book a 5/5 because it had a perfect execution of the ohh so popular super spy novel type. As well as it gave an aura of mystery and struggle for the characters but also was just a great read overall. This was well portrayed in the text when Charlie is fighting off the bad guy outside of the library. It really made you feel like you were there and were experiencing the spy action right in front of you. As well as when she ends up in grave danger solving a mystery that should in the real world be impossible or not even made to begin with. Both times in the story it showed how much of a super spy book it was and how it really affected the story making it really entertaining to read and that's why I gave it a 5/5.

The other reason that I gave it a 5/5 was because it has significant memories. I have been reading this book series sense around age 8 and this edition has just recently come out and while the book might be simple and not so age appropriate it still hits the spot and makes me feel like i'm back in elementary school relaxing in the book nook and reading with my friends about the great adventures and places that they would go it also gives me insight into somewhat of a simpler life one where i was given everything which might sound bad but it was pretty spectacular in the moment. as well as I just didn't know about so many things. the little looks people give indicating floods of emotions just went straight over my head and the different things that now i realize are problems now or might come off as weird were totally accepted and welcome maybe because of my good community and parents but also just because some of the books i was reading the people were outcasts and I just didn't even understand what that might feel like whereas now as life has gotten harder and just different i know exactly what some of those things mean the things that seemed so far from the truth as a kid are consistent in my life now.

My favorite quote from the book is on page 25 when it says "the best way to find something hidden by Einstein would be to find someone equally as intelligent" because it really summarizes the book well. it shows how intelligent charlie actually is comparing her to the smartest mind in his time einstein. as well as showing the hidden aspect implying that there is a spy aspect or at least mystery. And the quote itself has an aura of mystery because it is revealing something previously unknown to the person being told. That's why this quote is one of my favorites because it summarizes the book and is very mysterious

Charlie Thorne is a 15 year old supergenius who was smart enough to graduate from college before she turned 13 except her life took an unexpected turn when she was told by the CIA about a secret treasure Einstein hid something that could change the future of the world forever. She ended up solving all of the clues and finding the secret treasure then she really contemplated whether or not the world deserved the power that it held she figured that the whole world would take a blow if she released it so she kept it as well as being told or discovering through hacking or friends the other smartest scientific minds had some similar things that they hid from the world such as darwin, cleopatra and newton the main point of the book Charlie Thorne and the royal society. Where charlie ends up finding newton had another series of clues all leading to something BIG something she knew would be even worse than power newton released that could take the world by storm and she starts racing to solve the clues before some friends turned enemies can and just some straight out of mission impossible bad guys.





In my opinion the book is better than some people said the average listed on goodreads was (4.42) I thought it deserved a five straight but the main reason that i found was that it was people who had no idea what they were talking about they put in the effort to put in the zero stars but then wrote a single sentence to describe how horrible it was. And the only realistic reason I could find that someone would rate this book as even a four was just because it didn't measure up to the previous three books which were some of the best books i've ever read by one of the best authors i've ever read. The only other logical reason that someone would put it as lower that saw was because they were disappointed with how predictable it was which I guess I understand it was very predictable but then another thing people said was how amazing the last couple chapters where because of the insane plot twists and just the pure excitement of sitting on the edge of your seat waiting to see what was going to happen next because while the majority was predictable there were certainly parts where if i hadn't read on i would've been wondering for life.
But for the majority of the people that wrote the five star reviews i agree with, gibbs did a perfect job keeping the book interesting and unpredictable as well as making it just a genuinely fun addition to an amazing series that just made me want to read more and more of the book and i understand it is the waiting for the next book to come out that builds anticipation and makes you excited but i just wish he would go faster already haha im so excited for his next book as stated by many people on goodreads as well as stating that we had waited long enough for this edition waiting longer than a year and a half for the book to come out and in turn going on to having our expectations which were already high just brought to a new level because of the skyhigh effect that this book had on the readers me and the other five star raters on goodreads. This is why I think the book deserved better than it was given as well as why I agree with all the five star raters on goodreads.
1 review
June 5, 2025
It is such an amazing book, I love all of the series!! I kind of expected a little romance between Milana and Dante, since the previous one had a bit of that. I know it’s an adventure book but still… I also would have liked it more if Milana played a more important role in this book. Overall, I really enjoyed reading it and I would definitely recommend it!! I really hope that there's a book 5!
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