My 100% human-written Readers Guide to Guilty by Definition looks at this new book that felt a little like The DaVinci Code meets the Thursday Murder Club. A group of word nerds starts getting strange letters they need to decipher… perhaps from a murderer. I am ready to discuss and answer your questions!
Readers Guide to Guilty by Definition
Table of Contents:
- Jen’s Quick Take on Guilty by Definition
- Character List for Guilty by Definition
- Spoilers and The Ending Explained
Jen’s Quick Take on Guilty by Definition
- Guilty by Definition was so fun. If you are American, as I am, you probably have not heard of Susie Dent, who is a UK TV presenter (just like Richard Osman!)
- Guilty by Definition is set in Oxford
- The mystery centers around a group of employees at the Clarendon English Dictionary who receive a strange letter in the mail.
- They soon realize that the letter writer has intimate knowledge of a true crime case involving one of the dictionary word nerds.
- These amateur detectives are ON THE CASE
- Guilty by Definition felt a bit DaVinci Code (a puzzle book set in an academic environment) and part cozy mystery (think Marlow Murder Club)
- U.S. Publication date : September 30, 2025. Thanks to Sourcebooks for the advance copy!
Character List for Guilty by Definition
CED Employees
- Martha Thornhill: senior editor at the Clarendon English Dictionary
- Simon Turner: CED editor
- Safiya “Safi” Idowu: young British Nigerian CED editor
- Alex Monroe: fifty-something divorced mom and CED editor
- Jonathan Overton: consultant editor; author
- Mike Orme: former CED senior editor; now retired
Other Characters
- Gemma Waldegrave: Martha’s godmother, a literary agent
- Oliver Caldwell: police officer assigned to Charlie’s case
- Charlotte “Charlie” Thornhill: Martha’s sister; missing since 2010
- Olivia Overton: Jonathan’s wife
- Walter: original owner of a lot of old books and papers sold to Brin.
- Brin Edwards: antiquarian book dealer; Charlie’s former employer
- Rebecca Thornhill: Martha’s late mother
- Gabriel Thornhill: Martha’s father
- Tom: Charlie’s ex-boyfriend
- Tanya: Tom’s wife
Spoilers and The Ending Explained
Here are the top questions about the ending. Let me know in comments if you have more, or if you think I missed something or got anything mixed up!
Who Killed Charlie?
Olivia, Jonathan’s jealous wife, pushed Charlie down the stairs during an argument.
Jonathan helped her bury the body. Olivia rode Charlie’s bike and abandoned it. After Charlie’s death, Jonathan hoped to find the Common Book and publish it himself.
Who Killed Simon?
Also Olivia. At first Jonathan confesses, but the CED gang realizes it had to be Olivia.
Jonathan claimed that Simon realized he’d actually seen Jonathan burying the body years ago and tried to blackmail him. But Martha thinks he saw Olivia.
Who Stole Materials From the CED?
Simon, who fenced them with help from Brin, the book dealer.
Where Did the Common Book Come From and Who Hid it in the Bodelian Library?
Charlie bought the Common Book of Joan Hart, William Shakespeare’s sister, at an estate sale and realized what an extraordinary find it was. After her disappearance, Gabriel found the book hidden under a floorboard at the family home.
Gabriel then hid it in the Bodelian library. Jonathan sends a text to Gemma, asking her to pick it up. Gemma knew that Charlie had found something important and never said anything. She also must have suspected that Jonathan had something to do with Charlie’s disappearance.
How Did Jonathan Know it Was at the Bodelian Library?
He had also seen and decoded Chorus’s last letter.
Who was Chorus, the Letter Writer?
It was Gabriel, Charlie and Martha’s father. He’d figured out that Charlie was being accused of stealing materials from the CED. That she’d made a major discovery. But he didn’t know who killed her or why and thought he could get Martha to figure it out.
Questions? Comments? Think I missed anything or got something wrong? Leave me a comment!
Hi, Just a quick word to thank you for this thread (immediately after reading the book, I forgot who Chorus was) and to mention that in my edition, at least, Martha’s father is named Gabriel, not Gideon. I’ll also mention that the AI answer I got when I Googled “Who was “Chorus” in Guilty by Definition” was “Gideon.” So if I’m correct about that name, your website has likely been ingested by AI. Thank you again!
That is really funny. I got the name right in the character list but somehow decided to call him Gideon in the Q and A (I often mix up character names).
I fixed it so now Chat GPT will be wrong. I love it!!!
Your report still mistakenly says Gideon and earlier should say Jonathon helped her buy not buried.
You also need to define Walter in the character list.
Otherwise a good synopsis.
I thought I fixed that, but I now see that I called him Gideon throughout. Clearly I thought that should be his name but I will defer to the author lolol. But now Chat GPT, who apparently steals all my work, thinks his name is Gideon, so there’s that.