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The World's Greatest Detective

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By the end of our time together, someone in this house will be rich. Someone will be the World’s Greatest Detective. And someone, well, someone might be dead.

Detectives’ Row is full of talented investigators, but Toby Montrose isn’t one of them. He’s only an assistant at his uncle’s crime-solving business, and he’s not sure he’s even very good at that. But he sees his chance to prove he could be by entering Hugh Abernathy’s crime-solving contest in his uncle’s place.

Toby’s friend Ivy is the best detective around—or at least she thinks so. But she can’t show off her sleuthing skills and take the title because she’s not allowed to join the investigators’ ranks. Even though the competition is being held at her house.

Then a detective is found murdered before the games begin and his death becomes the World’s Greatest Mystery. And Toby and Ivy may be the only two who can crack the case.

In Caroline Carlson’s newest novel, hilarity and hijinks abound as the greatest detectives around try to solve the greatest mystery they’ve ever come across.

368 pages, Kindle Edition

First published May 16, 2017

78 people are currently reading
2580 people want to read

About the author

Caroline Carlson

8 books282 followers
Caroline Carlson is the author of funny and fantastical books for young readers, including The Very Nearly Honorable League of Pirates trilogy, The World’s Greatest Detective, and The Door at the End of the World. Her novels have won accolades from the New York Times, the American Booksellers Association, Bank Street College of Education, the American Library Association, and Junior Library Guild, among others.

Caroline holds a BA from Swarthmore College and an MFA in Writing for Children from Vermont College of Fine Arts. A Massachusetts native, she now lives in Pittsburgh with her family. You can visit her online at http://carolinecarlsonbooks.com.

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5 stars
300 (33%)
4 stars
417 (45%)
3 stars
167 (18%)
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19 (2%)
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Displaying 1 - 30 of 149 reviews
Profile Image for Genres and Journals *Tia*.
1,261 reviews359 followers
May 28, 2017
A fun read for 10 and up. Felt like a mix off Sherlock Holmes, Agatha Christie, The Westing Game, and Clue. Sure to please a lot of junior sleuths. 😊
Profile Image for Jamie Canaves.
1,143 reviews316 followers
March 21, 2025
Delightful! Ten-year-old Toby Montrose has been passed around homes ever since his parents disappeared. He’s currently staying on Detectives’ Row with his uncle and fears that if something goes wrong, as it always seems to, he’ll finally be out of options and be sent to an orphanage. Being that his uncle is having a hard time getting business, as most of the detectives on the Row are, Toby decides to lie his way into a detective competition to win a good chunk of cash and hopefully solve all his problems. Enter Ivy, a fellow child, already calling herself a detective who quite enjoys disguising and finding herself in trouble—she’s perfect! With any good mystery nothing goes as it should and Toby and Ivy find themselves partnering up which is delightful as their personalities clash and they have to prove that children are perfectly capable of being great detectives. A perfect read for fans of cozy mysteries!

--from Book Riot's Unusual Suspects newsletter: A Con Artist, Delightful Detectives, and My New Favorite Detective
http://link.bookriot.com/view/56a8200...
Profile Image for Kate.
50 reviews
December 11, 2025
I read this out loud to my family, and it was delightful with some truly great laugh out loud moments, including one scene early on in the book that I think will be ingrained in my brain for a long time because it was written so well that I was there in the room experiencing it.

Now that I've read several of Caroline Carlson's books, I am realizing what I love so much about them: the writing is great and I often really love her word choices, the characters are fun and interesting (this is the second book with a supporting/secondary character I would happily read an entire separate book about), the humor is spot on and works for kids and adults (and we don't always laugh at the same things!), there are usually some fun and unexpected surprises, and there are also just some really good life messages.

I do personally know the author, which makes me a little biased, but I'd also love her books if I did not - and have recommended them to others who do not know her who have also loved them. Can't wait to read the next one aloud to my family, which, for us, is the The Door at the End of the World.
8 reviews
January 7, 2017
This middle grade mystery was so fun! The characters were interesting and engaging. I was kept guessing the whole time, and just when I was sure I knew the answer, there was a dramatic twist ending that I didn't see coming at all! (Of course, as this book demonstrates, sometimes children are better detectives than grown ups.) I would recommend this to any mystery-loving child 9 and up (due to the prevalence of, of course, murder and a somewhat intense scene towards the end).
Profile Image for Tracy .
862 reviews15 followers
March 12, 2017
Sweet. I downloaded and read it because the description reminded me of The Westing Game, one of my favorite books ever. It wasn't really the same writing style, but the charm of smart children trying to solve a mystery still makes me smile.
Profile Image for Jessica Lawson.
Author 6 books110 followers
October 4, 2017
Oh goodness, the WRITING and VOICE in this were glorious. This is one of my favorite types of books~ Britishy mysteries. I adored the characters and the red herrings and the outcome. Loved it!
Profile Image for Melissa Perret.
227 reviews1 follower
July 29, 2019
This was so fun, I absolutely loved it! Cute and well written.
Profile Image for Caryn - iam.caryn.
787 reviews87 followers
March 29, 2021
I’m telling you right now, every single middle grade reader is guaranteed to adore this book. The same can be said to mystery lovers of any age. A fun, twisty and oh so entertaining little mystery that keeps you hooked on every page.

Toby, the narrator, is so incredibly sweet, and Ivy is delightfully quirky. I loved them both so much!

The story itself was written incredibly well. It’s reminiscent of classic Doyle or Christie tales, but written for a younger audience. This enjoyable book left me with a smile on my face.
Profile Image for Leah.
1,976 reviews
October 15, 2017
I thought this story was too slow, and it would have been more enjoyable if it had been significantly shorter. I did like the ending, though. It was something that I didn't expect. The characters were okay. I liked Ivy more than Toby. I thought he was too bland, not an interesting main character.
Profile Image for Lily.
9 reviews
November 8, 2025
cuteeee. ivy is lowkey a brat but the storyline was really cute and i loved the character development
Profile Image for Lindsey (Books for Christian Girls).
2,157 reviews5,096 followers
May 10, 2020
Hmm. Let’s first chat about how cute this cover is, yes? It’s quite lovely.
Now, to the actual story.
Mysteries are always a genre that I’m willing to read, but I don’t believe I’ve read many (secular) middle grade mysteries. (Besides my favorite series, The Mysterious Benedict Society. But, sadly, I am not here to fangirl and giggle over that beloved series.) This book had me curious because I though it may be similar to a game of Clue. I’m still not sure how I feel about a middle grade book including a murder and a villain pointing a pistol at our main children characters. It was decently clean, but I wouldn't say I really enjoyed it. Oh, well.


Content:
* “My god” (twice), “Egads” (once), and “damned” (once) are said.
* All about a murder mystery (that was supposed to be fake/acted, but a real one occurs. The body, corpses, skeletons, poison, and blood/bleeding are all prevalent and range from not-detailed to barely-above-not-detailed.)
* A pistol is aimed at our main characters and the villain talks about shooting them.
* Ivy can come across as a little bloodthirsty and talks about deceiving people with confidence so they will believe you.
* Some mentions of mummies, dead animals, and goddesses.
Profile Image for Belles Middle Grade Library.
864 reviews
January 16, 2021
Wow! What a great mystery whodunnit! I absolutely loved this! This for all the junior sleuths in training! Toby has been bounced around from one relative to another since his parents disappearance/suspected death. The trouble always finds him, & he is shipped to the next one. He’s now w/his Uncle Gabriel who is a detective living on “detective row”. But business is slow for all of the detectives , along w/his uncle. Except for the famous “worlds greatest detective” Hugh Abernathy. Toby is his uncles assistant, but he wants to do more. Be a detective like his uncle & Abernathy. He wants to make himself useful, & help his uncles business so his uncle won’t have any reasons to send him away. He starts learning how to be a detective. A girl has been following him-Ivy-& they end up becoming friends when Mr Abernathy hosts a competition at Ivy’s huge home. It’s a whodunnit competition, & the winner wins $10,000 & title of worlds greatest detective(Abernathy is retiring). His uncle can’t stand Abernathy & refuses. Toby goes in his place w/a cover story. The competition takes a crazy turn, & things become serious & very dangerous. It’s up to Toby & Ivy to crack the case. I loved Toby, & my heart broke for him. For all he had been through, & then to even have the thought to do something so his uncle wouldn’t have to send him away-heartbreaking. Ivy was a hoot lol so much personality, spunk, & dramatics. There are so many twists in the book, & the one at the end blew me away. I did NOT see that ending coming. Loved it. This was full of mystery, tension, & suspense. So hard to put it down when I had to. I loved all the characters in here-& what characters they were lol some scared me, but most of them had me laughing out loud. Highly recommend! Love this amazing cover by Júlia Sardà too!💜
Profile Image for Connie.
921 reviews7 followers
March 6, 2018
I have found a book to recommend to our middle-grade grandchildren! Toby thinks trouble follows him, and it does seem so. When his parents go missing, he finally ends up living with his detective Uncle Gabriel who is struggling financially. Toby goes to desperate measures to win the $10,000 prize offered to the detective who can solve a staged death and then become "The World's Greatest Detective." Before the game starts, a detective is murdered. Toby and wanna-be detective Ivy join forces in the competition.
The story was fast, captivating, fun, and suspenseful.
Profile Image for Jürgen.
Author 2 books61 followers
May 31, 2020
Grundsätzlich nette Geschichte, die aber ohne wirklich Spannungsbögen vor sich hin plätschert. Eher für jüngere (10-12) geeignet. Die Charaktere waren mir zu flach und die Logik blieb dann und wann auf der Strecke. Eine Kleinigkeit, die mich aber sehr gestört hat: Es ermitttelt ein 'Chief Constable', also der Polizeichef einer Stadt- oder Distriktpolizei, und der gute Mann wird durchgehend als 'Constable' angesprochen.
Profile Image for Jamie.
564 reviews4 followers
June 14, 2017
I expected to enjoy this book, and I did. I expected a slightly predicable mystery, and I was pleasantly surprised to find that this author does not underestimate children. The clues were all there, but there was so much more to the story. I stayed up until 2:00 AM finishing the book because the characters mattered to me and I knew I wouldn't be able to sleep until their story was resolved.

My daughter has read (and loves) Carlson's pirate series. It is now on my must read list.
234 reviews1 follower
September 3, 2017
I would give this a 3+ as it was slow to get going but the end was good and I hope there are more stories about Toby and Ivy.
Profile Image for Neisa.
42 reviews11 followers
June 20, 2020
Great book for adults and kids! If you love a good mystery you'll enjoy this book!
Profile Image for Vicki.
179 reviews3 followers
March 23, 2024
Fun middle grade detective story❤
Profile Image for Allenh.
29 reviews2 followers
June 3, 2023
I don’t like it I love it it is thrilling adventurous and surprising it is not who you think it is-Simon :)


Profile Image for Joy.
59 reviews1 follower
May 20, 2017
Witty and satisfying! I was expecting a fun adventure, but the story had a layer of emotional depth I wasn't expecting but really enjoyed. Ready for the next one.
Profile Image for Tiffany.
637 reviews138 followers
November 24, 2020
Im on the hunt for good middle grade mysteries for my daughter, but I pre-read them to make sure they’re not too intense for her age range. While this book does have a murder & a dangerous climax (main character has a gun pointed at them), it’s not at all gruesome. The mystery was fun, the characters were great & memorable & the end was heart-warming. Highly recommend to all mystery-loving kids!

Also, for parents who are concerned about language, this book has one use of “damned,” which felt a bit out of place in the rest of the book.
Profile Image for Steph Heinz.
2 reviews5 followers
January 3, 2017
With tonal similarities to A Series of Unfortunate Events, THE WORLD'S GREATEST DETECTIVE embraces the tension of a murder mystery while remaining a fun adventure for younger readers. Deeper still, it tells the story of a boy plagued by personified 'trouble' and concerns far beyond his young age as Toby works to find not only a murderer, but himself and his place in the world.
43 reviews
May 14, 2020
Oh my gosh. This book is a must read. It is so exciting and mysterious. I love how many things happened, like dead ends and capturing. Then in the last hundred pages or so, you find out everything. I couldn't believe who actually murdered who, really. This book is so exciting and I suggest it to anyone who likes mystery and surprises.
Profile Image for Kellee Moye.
2,923 reviews339 followers
June 14, 2025
Over Spring Break, Trent and I were driving a lot, so we decided to listen to an audiobook, and Trent wanted a murder mystery. I am so glad that he choose this one! It is a kid’s version of Sherlock Holmes mixed with Clue with two main characters who are a perfect duo. We definitely recommend this to anyone who loves a good mystery!
Displaying 1 - 30 of 149 reviews

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