Mystery Rules

In today’s episode, Brook and Sarah discuss the rules of mystery from the Golden Age, including from the Detection Club, S.S. van Dyne, and Raymond Chandler.

Discussed and mentioned

The Notebooks of Raymond Chandler (1991) Raymond Chandler

“12 Notes on the Mystery Story” (1948) Raymond Chandler

“Twenty Rules for Detective Stories” (1928) S.S. Van Dine

“10 Commandments for Mystery Fiction” (1929) Ronald Knox

Thursday Murder Club (2020) Richard Osman

Marlow Murder Club (2022) Robert Thorogood

Only Murders in the Building (2021) Disney+/hulu

Related Episodes

Interactive Mysteries (released September 29, 2026)

Mysteries Without Murder (released September 27, 2022)

For more information

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Transcript

This transcript is generated by a computer and there may be some mis-spellings and strange punctuation. We try to catch these before posting, but some things slip through.

Sarah	Welcome to Clued in Mystery. I’m Sarah.
Brook	And I’m Brook, and we both love mystery.
Sarah	Hi, Brook.
Brook	Hi, Sarah. I wonder if people know that there are rules to writing a mystery.
Sarah	Well, and there’s not just one set of rules, Brook. There are many variations, and that’s what we’re going to be talking about today. We often refer to the Golden Age of Mystery, and that period is generally the 1920s and the 1930s, although many of the authors who came to fame during that time continued to write in the decades beyond. As you said, we also refer to the rules of mystery. Arguably the most famous version is the set credited to Ronald Knox of the Detection Club. These were the Ten Rules or Commandments originally drafted by Knox in 1929.
Sarah	This was not the first time that someone tried to codify The Rules of Mystery. American author S.S. Van Dine shared 20 rules in 1928 in The American Magazine. And although Knox’s rules were often considered to be tongue-in-cheek, Van Dine took his rules a little more seriously, according to Martin Edwards. Raymond Chandler also offered his own set of rules in 1948. And I found a copy in a book called The Notebooks of Raymond Chandler. And I, Brook, have just enjoyed reading this so much and highly recommend it to anybody who’s even a little bit interested in mystery.
Sarah	The common theme among all of these sets of rules is fair play. That is, the reader must be given enough information to solve the crime along with the detective. And we can maybe talk about some of the ways that these different sets of rules set that out. And I think it would be also really interesting, Brook, for us to talk about the ways that the rules differ.
Brook	Yes, that sounds great, Sarah. um You know, when we were… kind of reading through the different sets of rules and I had not come across the Chandler rules. So, I’m very interested to hear today what he recommends. I was thinking how, you know, no other least commercial genre has this kind of strict rules. There’s definitely formulas to romance. You kind of know what to expect. A horror book has like a sort of story arc that’s very familiar.
Brook	But, as far as I can really tell, this is the genre where there’s like “these are the things that must or should not happen”. And I think it comes back exactly to what you mentioned right off the top is because this is the genre where you want that fair play with the reader.
Sarah	Yeah, and and I think there’s a… couple of things and you I’m thinking about the conversation that we recently had with Jessica Brody where she talked about structure and there are some rules around structure or expectations that you have to meet to make it a satisfying mystery. And I think that’s true, like you say, for any genre, right? In in horror, in romance, mystery, science fiction, all of those. There are there are conventions that are associated with those genres that if you stray too far from those, readers who are very familiar with those conventions are not going to like your book.
Brook	Mm hmm. Right.
Sarah	But I think what we’re talking about in the rules, it’s not so much about the structure. But ah about the mystery itself and ah And and its solution and the way that it’s solved. Um and so, at least three different authors have set out rules and I think you know if you did a little google search you would find multiple other variations that people have at taken these rules or the you know collectively, what is this 32 rules between Knox, between Knox, Chandler and Van Dine.
Sarah	And so there are some duplicates, absolutely, that like… there there are some common elements across all three of them. But there are some some differences and it really is. I think in how each of these authors felt a mystery should play out.
Brook	Right. Right. And okay, so let’s talk about some of those things that are… Very similar, like for our listeners who maybe haven’t ever looked at these rules, like what we’re talking about here. um One thing that is very similar is obviously the idea of the fair play and this is that all the clues all the evidence should be available to the reader at some point in the story in order for them to come to the same conclusion as the sleuth. And that’s probably the biggest… i As I said before, I’ve never looked into Chandler, but I’ve read his books and I’m pretty sure he probably believes in fair play. They want readers to have a fighting chance to solve the mystery themselves. And I think that is one. thing that is equal across the board on these.
Sarah	Yeah, and, and each of them kind of get to that fair play in slightly different ways. So, the Detection Club, and “the criminal must be mentioned in the early part of the story but must not be anyone whose thoughts the reader has been allowed to know”. So, the Detection Club or Ronald Knox really felt that you know you can’t introduce the culprit. in the final pages of the of the book. As readers, we can’t know what this character is thinking, which I think is something that has been strayed from again and again and works really well when it when it’s something that has been strayed away from. So it’s not one of those sacrosanct rules. um But that first part that the criminal must be mentioned in the early part of the story.
Sarah	Other fair play um or other statements that support fair play that the Detection Club or Ronald Knox made. um “The detective is bound to declare any clues which he may discover.” So we can’t have the detective learned something and then keep that to himself. That’s… kind of what the sidekick is for is for him to discuss that with the sidekick. And then.
Sarah	Knox set out a rule about the sidekick saying “the sidekick of the detective, the Watson, must not conceal from the reader any thoughts which pass through his mind. His intelligence must be slightly, but very slightly, below that of the average reader.”
Brook	That’s right.
Sarah	And then. So, S.S. Van Dine. The way that he framed fair play. This is his very first rule. “The reader must have equal opportunity with the detective for solving the mystery. All clues must be plainly stated and described.” And then the second one is “no willful tricks or deceptions may be played on the reader other than those played legitimately by the criminal on the detective himself.”
Brook	That’s right. And I think something that else that falls into this category that is… quite equal across the board is The idea of supernatural or um divine solutions I guess. Knox says, “All supernatural or preternatural agencies are ruled out as a matter of course.” And Van Dine agrees in a way by saying, “the problem of the crime must be solved by strictly naturalistic means um He goes on to say methods such as slate writing, Ouija boards, mind reading, seances are taboo.” We can all definitely think of stories that use those scenes or devices and so there’s like another rule that has probably been bent.
Sarah	Yeah. and And Chandler had something similar. He said “it must be realistic in character setting and atmosphere. It must be about real people in a real world.” But as you say, that is that you know criteria that these authors have set out is one that several authors have played with and and played with quite successfully.
Sarah	In terms of those rules that must not be broken, I do think that that, that one about um that the detective must reveal everything that he learns or or suspects. um I mean i I think that’s pretty fundamental. Right. Because it it is not satisfying. I can think of lots of um television shows that have done this where uh you know the detective sees something and then there’s no revelation about what he’s figured out as a result. We the viewers don’t get to see what he has seen. And then it’s not until the conclusion of the story where he says, “well, effectively remember 20 minutes ago when I looked inside this box, right, that you didn’t get to look in. That told me that. you know so-and-so was the was the murderer.” um And yeah, that’s not a particularly. ah that’s not a particularly satisfying experience because then you don’t get to play along. Right. You’re not part of the investigative team. Which I think is part of the the the real appeal of these of these stories.
Brook	Yeah, I agree. And this actually layers in really nicely with our discussion about interactive mysteries this season. Because even if… the book isn’t specifically written to be interactive in the way like say a choose your own adventure book is As a mystery reader, we want to take part in this intellectual puzzle. And. Yeah, you’re you’re right. If you don’t have all the information that the detective does, then it’s just no fun. And I hate those shows where you see their face and they’re shocked, but then they never turn the camera around to show you what they’re so interested in. I sometimes have to turn off the television. I’m like, this isn’t going to be any fun anyway.
Sarah	Yeah. Well, and so S.S. van Dine, he wrote out 20. Oh no, my math was wrong. It was 42 rules between all of these, isn’t it?
Brook	Oh, that’s right. 42.
Sarah	Uh, anyway, he wrote out, ah you know a few that. I think these are rules that are broken again and again and again. So one. Um, “There must be no love interest in the story.”
Sarah	Another, “there simply must be a corpse in a detective novel. And the deader the corpse, the better. No lesser crime than murder will suffice.” So you know we have an episode where we talk about. Mysteries Without Murder, and and they can be very popular and um equally satisfying. Right.
Brook	Mm hmm.
Sarah	ah And then “there must be one detective. ah to bring the minds of three or four, sometimes a gang of detectives to bear on a problem is not only to disperse the interest and break the direct thread of logic, but to take an unfair advantage of the reader who at the outset pits his mind against that of the detective.” Again, we have talked about books where It’s… particularly amateur sleuths, right? A group of amateur sleuths. So, the Robert Thorogood series. Is it called The Marlowe Murders?
Brook	Yes. Mm hmm.
Sarah	uh or the Thursday Murder Club right like These are groups of people who have taken an interest in solving, solving a crime. and Those books only work because it is a group.
Brook	Yeah. Only Murders in the Building. That wouldn’t be any fun with just Mabel.
Sarah	Exactly yeah you need that interplay between the characters. Because they use each other to come up with the with the solution.
Brook	Another one of his that is often broken to the point of being cliche is “a servant must not be chosen by the author as the culprit.” And I mean, we literally have the saying the butler did it right because and perhaps that’s the reason why Van Dine made so many of these rules. He actually thought that these things had been overdone, which I had to kind of… chuckle because he’s writing this in 1928. Like, okay, people, no more butlers, right?
Brook	Like, this is still quite early in the days of mystery. But, you know, he thought that these things were already too rote, too cliche. So, you know, no love interests. All these things that we’ve outlined, no seances. um because they were overdone and clearly that’s not the case because here we are a hundred years later still enjoying some of the stories that intentionally break his rules.
Sarah	I think you’re right, Brook, that he. was writing in response to Uh, things that he was seeing happening. And I think Knox was probably the same, right? um The on The limit on secret passageways, for example, ah or um not having twins as the solution, right. So you know these things that you just see again and again, and even though it wasn’t phrased in a what we would consider a particularly um correct way now his Knox’s um ah criticism of having the criminal be a foreigner right someone who is from another country or another culture and i think he was writing that not to. uh be racist but to say like we shouldn’t be racist, right?
Brook	Yeah, the opposite of racist.
Sarah	Exactly. Like we we shouldn’t be. um Blaming. someone just because they are from another another country
Brook	Right. Um. I think that both the secret passageways and the twins rule still go back to fair play, though, because the way that those can get in the way of a good mystery is that it creates this coincidental or too simple explanation. And like at the end you’re like, oh there was a twin like And to me, that’s still just an issue of fair play.
Sarah	Yeah, I think you’re right, Brook. and i think fundamentally that’s what these rules are about is how do we make sure that we are honoring the readers. Right. By giving them something that, that they enjoy and is satisfying.
Brook	Mm hmm.
Brook	Yeah, let’s talk a little bit about the Detection Club’s take on these rules and how they used them, because I think that their, um… use was much more liberal and kind of tongue in cheek. But, these rules were probably for at least a bit only really discussed between their invite-only members, I would say. And if you’ve listened to our episode about the Detection Club, you’ll remember that they took this oath to uphold the rules as they held a human school named Eric. um
Brook	So they would go through the list and in part it says “do you promise that your detectives shall well and truly detect the crimes present to them using those wits which it may please you to bestow upon them and not placing reliance on nor making use of divine revelation, feminine intuition, mumbo jumbo, jiggery-pokery, coincidence or act of God. I mean, very fun, but still this portraying a lot of the same things we’ve already talked about. ah
Brook	I think probably the way you can know how much fun they were having with this though is the warning and the curses that they had to accept that if they broke these rules, things that might happen to them is “may other writers anticipate your plots. May your publishers do you down in your contracts. May total strangers sue you for libel. May your pages swarm with misprints. May your sales continually diminish.” I mean, so much fun.
Sarah	I love the idea that they just wanted to protect the integrity of the genre.
Brook	Definitely. And once again, I’m thinking of something that Jessica Brody said to us that, because we know that the members of this club did break the rules. And I don’t think many of their sales continually diminished. But Jessica mentioned, and I think it was really smart that if you were going to break a rule, that there needs to be a purpose for it and a reason for it and do it in a very intentional way. And so let’s take, for instance, the idea of twins. You can write a fantastic mystery about twins, but you do it in an intentional and fair way. And then
Brook	And then you can, quote unquote, break that rule.
Sarah	Mm hmm. i think that’s a that’s a good point so when we’re talking about authors breaking these rules a lot of the time when it works, it’s because it’s been done with that with that thought behind it
Brook	Mm hmm.
Sarah	A couple of rules that I think were interesting in Van Dine’s list. Um, one is about the professional criminal. So “A, a professional criminal must never be shouldered with the guilt of the crime in a detective story. Crimes by housebreakers and bandits are the province of the police department, not of authors and brilliant amateur detectives.
Brook	Yeah, isn’t that interesting? It almost… means that he was like leaning towards the cozy end of the spectrum. doesn’t it? However, their sleuths weren’t necessarily always amateur. So, I found this to be kind of an interesting dichotomy there.
Sarah	Yeah, that’s an that’s an interesting observation. And and often… Um, The Golden Age is. um considered to be cozy although we know that Agatha Christie wasn’t a cozy author.
Sarah	So. um One thing that Chandler wrote is … he split this over two rules. So number five is “it must have a sound story value apart from the mystery element i .e the investigation itself must be an adventure worth reading” And then number six “to achieve this it must have some form of suspense even if only intellectual This does not mean menace, and especially it does not mean that the detective must be menaced by grave personal danger. This last is a trend and, like all trends, will exhaust itself by over-imitation.”
Brook	There again, he’s talking about how. these things have already been sort of tired out.
Sarah	Yeah, and he goes on to say, there must be conflict, physical, ethical or emotional, and there must be some element of danger in the broadest sense of the world word. So he doesn’t. He says there there needs to be some tension, but you can’t have only tension. Right. That gets too much for the reader.
Brook	Yeah, and I think that’s ah i think that’s ah actually a great… tip for authors is to not continually be adding conflict without having some sort of little resolutions along the way. So I enjoy that that tip.
Sarah	Another thing that Chandler wrote is that “It must punish the criminal in one way or another, not necessarily by operation of the law. It is a part of the logic of detection. If the detective fails to resolve the consequences of the crime, the story is an unresolved chord and leaves irritation behind it.
Brook	Yes, it does. I agree with that. There needs to be some sense of justice. And he’s right. It’s not always that the person goes to jail, but… Somehow that villain you know, gets their due.
Sarah	Yeah. And. is An interesting… interesting thing about Chandler’s in this book that I found the um his list. He’s… added addenda. So he’s got another. Hmm. dozen or so. uh rules so now i think we’re up over 50.
Sarah	Um, And he says, Um, In his addenda here, he talks about that. um “Love interest nearly always weakens a mystery story because it creates a certain type of suspense that is antagonistic and not complementary to the detective’s struggle to solve the problem.” So I think it’s really interesting that. romance and and love are elements that appear in at least two of these lists of things that shouldn’t be included in mysteries and as we say Those have been done quite… quite successfully.
Brook	Well… And. Don’t we have like the femme fatale in Chandler books? like Which I realize that’s not like a true romance story, but there’s usually some sort of push and pull between the beautiful woman and… the detective. Maybe I’m, maybe I’m ascribing stories to him that aren’t fair, but that feels very Chandler to me.
Sarah	But maybe it’s not romance. Right?
Brook	Yeah, I guess we need to think about what… men from this era. Would consider romance. Maybe they’re talking about very mushy. you know, love scenes kind of a thing versus just the interplay between men and women.
Sarah	Yeah, and and he goes on. He actually has a couple of rules for in this addendum where um he talks about. Romance. so um It was point 6 where. He says, “love interest nearly always weakens a mystery. and He concludes that point by saying a really good detective never gets married. He would lose his detachment. And this detachment is part of his charm.”
Sarah	And then the seventh point is. The fact that love interest is played up in the big magazines and on the screen doesn’t make it artistic. Women are supposed to be the targets of magazine fiction and movies.
Sarah	The magazines are not interested in mystery writing as an art. They are not interested in any kind of writing as an art. So. He’s really making some. Some commentary on. Like. What else is being produced? at the time. Right. So I think that these were he wrote these down. apparently in 1948. um So, you know. What? other kind of media was available at the end of the 1940s.
Brook	Yeah that’s super interesting.
Sarah	Well, Brook, this is not the only conversation that we are going to be having about the rules because we are very fortunate to have Frances come back bookseller from the Chronicles of Crime to come back and talk about this topic with us.
Brook	Yes, I cannot wait for that interview. Frances is so knowledgeable about the mystery genre, and I’m sure we’re going to have a wonderful conversation. But for now, listeners, thank you for joining us on Clued in Mystery. I’m Brook.
Sarah	And I’m Sarah. And we both love mystery.