Dear friends,

It was last autumn, when I was rereading Agatha Christie's The Mysterious Affair at Styles for the Green Penguin Book Club episode on that book, that I began to wonder what the point of the "poison book" really was.

I'm sure you have come across this phenomenon in Christie and other golden age detective fiction too: a character wants to buy a poison and in order to do so she must put her name and address in a book or register kept by the retailer. Often this entry is later shown to be falsified by the subsequent murder investigation, but there never seems to be any serious penalty for this fraud. It's usually just one clue among many others and it didn't seem to be a deterrent to any would-be poisoners. So why do these books even exist?

To find out, I asked Dr Kathryn Harkup, chemist and author of science books including V is for Venom: Agatha Christie's Chemicals of Death, to return to the show to guide me through the twists and turns of nineteenth century pharmaceutical regulation in Britain. Because that is where the poison book originated — with the Arsenic Act of 1851.

Partially in response to arsenic's growing reputation as a deadly and highly available domestic poison, the government made its first attempt to curb who could get their hands on dangerous chemicals. As you'll hear in today's new episode, two more laws followed in the subsequent decades which tried (with limited success) to improve the situation. But by the time the books you'll hear us talking about (see below!) were published in the 1920s and 1930s, the poison book was still such an accepted part of the British shopping experience that interwar crime writers felt no need to explain it to their readers.

As Kathryn and I were planning this episode, we went back and forth on whether it made more sense to look at this subject in terms of the legislative chronology or through the golden age detective fiction in which the poison book appeared. Ultimately we decided to go through the laws in order and talk about the different questions that arose in each novel as we came to them. I thought I might just give you a little taster of the books we covered here before you dive into the full episode.

Obviously we talked about The Mysterious Affair at Styles, with its fiendish poisoning plot and clever use of the poison book. But we also covered Strong Poison by Dorothy L. Sayers in some detail, since the poison book is a major piece of evidence in the trial of Harriet Vane with which the novel opens. Vane, of course, is accused of poisoning her former lover with arsenic, and her defence is complicated by the fact that she freely admits she had been buying the drug and signing false names for it as part of research for a novel! During our conversation, Kathryn wondered whether Dorothy L. Sayers had ever tested this out for herself, and now I can't stop thinking about this myself. She was so keen on accuracy...

Another title I greatly enjoyed diving into for this episode was Family Matters by Anthony Rolls (keen newsletter readers may remember me mentioning this in our most recent "Reading Recommendation" post). I've never read anything like the poisoning plot in this book and it was fascinating to hear Kathryn's take on the science of it. It also demonstrates another way in which the poison book system was ineffective at preventing crimes. At least one of the substances in this story is known to be highly toxic yet is exempted from the provisions of the law, making it freely available to purchase everywhere. Gulp.

With so much discussion of arsenic, we had to delve into The Wychford Poisoning Case by Anthony Berkeley too. Aside from a couple of bizarre spanking-based scenes (!), this novel is an excellent retelling of the Florence Maybrick case from the 1880s. Berkeley relocates it from Liverpool to the Home Counties and updates the period to the 1920s, but keeps the "too much arsenic" problem that was central to the real-life case.

My memories of this book from when I made the Anthony Berkeley episode with Martin Edwards back in 2020 were that it wasn't that good, but I was pleasantly surprised when I revisited it last month. Some of Roger Sheringham's antics did make me roll my eyes, but Berkeley's facility with turning actual murders into clever fiction was more impressive this time round.

As an extra bonus for loyal newsletter readers who have made it this far, I thought I would also flag a short story that we did discuss, but that had to be cut from the main episode for time. This is “The Boat Race Murder” by David Winser from 1942, which can be found in the British Library Crime Classics anthology Setting Scores. This features the misuse of a patent medicine and the falsification of a poison book... David Winser was both a rowing blue and a medical student, so it's safe to assume that at least some of this story drew on his own experiences. He was sadly killed in action in WW2 in 1944 and so did not live to write more crime fiction, but this story is well worth looking up, I recommend it.

And do let me know as you are reading around the classic crime genre if you discover any other interesting instances of the poison book in golden age detective fiction. I have a feeling that I am only at the beginning of my obsession with this...

Until next time,

Caroline

You can listen to every episode of Shedunnit at shedunnitshow.com or on all major podcast apps. Selected episodes are available on BBC Sounds. There are also transcripts of all episodes on the website. The podcast is now newsletter-only — we're not updating social media — so if you'd like to spread the word about the show consider forwarding this email to a mystery-loving friend with the addition of a personal recommendation. Links to Blackwell’s are affiliate links, meaning that the podcast receives a small commission when you purchase a book there (the price remains the same for you).

Dear friends,

There are certain topics that are too perfect for Shedunnit, and so even though I think about them all the time, I have never made an episode about them. Sherlock Holmes is one of these.

Let me explain.

The influence of Arthur Conan Doyle's creation on the golden age of detective fiction cannot be overstated. Some of the foremost mystery writers of the 1920s and 1930s — including Agatha Christie and Dorothy L. Sayers — were self-professed fans. Sayers was even something of a Sherlockian; her essay “The Dates in the Red-Headed League” is an exercise in scholarly pedantry that has to be seen to be believed.

Even beyond the explicit references to Holmes as a character, the fundamental structures of client-detective and Holmes-Watson are everywhere in the puzzle-based mystery. It's no accident that an elderly and ailing Conan Doyle was asked to be the first president of the Detection Club (he sadly passed away soon after receiving the invitation and the honour went to G.K. Chesterton instead).

It's this ubiquity that has stopped me every time I have considered trying to put together a "Sherlock Holmes" episode of Shedunnit. There is just so much to say, and such a knowledgeable audience out there, that I fear anything I might do would be incomplete and unoriginal. And so, I avoid the great detective in favour of subjects that are easier to encapsulate in a 25-35 minute podcast episode.

But the podcast's archive is not a completely Sherlock-free zone. Such is his fame that even when I am avoiding him, he creeps in. Now that we are almost at the midpoint of 2025, I am looking ahead to the first half of next year and thinking about the topics I might cover (yes, I do plan that far in advance)... Maybe it's time to visit 221B Baker Street at last? Let us review his appearances so far, at least.

He popped up earlier this year, in fact, in the "Agatha Christie's Taste in Crime Fiction" episode:

As is so often the case with any consideration of twentieth century crime fiction, Sherlock Holmes is where we must begin. And I think there is a fair case to be made that that is where Agatha Christie began too, in her reading of crime fiction. In her autobiography she explains that it was her sister Madge who, was eleven years older, who introduced her to the sleuth of 221B Baker Street, via the 1892 story "The Adventure of the Blue Carbuncle". Although the chronology nor indeed the contents of the autobiography is not always entirely to be trusted, Christie includes this recollection about Madge and Conan Doyle in a section about this married sister's visit home to Torquay just after her son was born, which was at the end of the summer in 1903. Agatha would have been thirteen, which in my view is just the age to start reading the adventures of Holmes and Watson. She records that aside from "The Blue Carbuncle", it was "The Red-Headed League" and "The Five Orange Pips", which also appeared in 1892's The Adventures of Sherlock Holmes, that she liked best. More experienced Sherlockians might have theories about what unites these three stories, but to me it seems as if these are all tales with an origin point in the mundane and domestic — the loss of a Christmas goose, a strange job advertisement, a peculiar letter. And we know, of course, what good use Agatha herself was going to put such innocuous elements in her own fiction.

It tickles me enormously to think of a teenage Agatha Christie poring over her Sherlock Holmes stories.

As keen listeners of the 2022 live episode "A Prize Mystery" might remember, before she became very famous Agatha Christie was a keen entrant in a number of "competition mysteries". I don't know if she entered this one judged by Conan Doyle himself, but I'd like to think she would have had a go:

In March 1927, Sir Arthur Conan Doyle published an article in the Strand magazine in which he finally bid farewell to readers of Sherlock Holmes — making rueful reference to the fact that he had, of course, tried the dispense with the character once already only to resurrect him due to popular demand. But now, as the 1920s were coming to a close, the last collection of Holmes short stories, The Case-Book of Sherlock Holmes was about to be published... To mark this moment of farewell, then, he proposed what he called a small competition as "a little test of the opinion of the public". Conan Doyle wrote his own list of what he considered to be the twelve best Sherlock Holmes stories and left this in a sealed envelope with the editor of the Strand. The reader who wrote in with a list of a dozen titles that mostly closely coincided with the author's own selection would win £100 and an autographed copy of his autobiography, Memories and Adventures. It's not quite the solution to a crime, but it is still a contest between writer and reader. Who knew Sherlock Holmes better, his creator or his fans?

You can read Conan Doyle's full essay and selection here. Apparently the competition winner correctly guessed ten out of twelve stories.

In my 2021 reading experiment, "A Century Of Whodunnits", I read The Return of Sherlock Holmes as my book from the first decade of the twentieth century. Here's what I made of it then:

Turning the pages, it felt a bit like I was reading a kind of source text out of which everything in the next couple of decades was going to expand. "The Adventure of the Empty House" is a clever locked room mystery. "The Adventure of the Dancing Men" is a case that turns on code breaking. "The Adventure of the Solitary Cyclist" is an inheritance mystery. "The Adventure of the Priory School" features a criminal that deliberately tries to hoodwink the detective when it comes to forensic observation. "The Adventure of the Abbey Grange" sees the detective act not only as investigator, but judge and jury too. I could go on. Each story contains at least one aspect that other writers would enhance and develop into entire plots and subgenres in the decades to come.

I think perhaps part of my hesitation to make an episode dedicated solely to Sherlock Holmes stems from the fact that it's been a long time since I read the actual stories. I consume a lot of Holmes at second and third hand, it feels like, through the detective fiction that was influenced by Conan Doyle and the ever-present adaptations, but it's rare that I read the real thing.

Lastly, since the English season is well under way, I must just touch on the connection between Conan Doyle, crime and cricket. Even though the author was a keen cricketer himself, there are only passing references to the sport in two Sherlock Holmes stories, I learned from making the "Cricket and Crime" episode. That hasn't stopped fans from filling in that gap, though, as my guest Andrew Green explained:

There's two novels in particular that place Holmes at some very kind of significant cricket matches. One of those is by Arunabha Sengupta, and it's a book called Sherlock Holmes and the Birth of the Ashes, which places Holmes at the famous match where the bales were burned to create the ashes, which is what is played for every time England and Australia play each other in a test series. And another book called Sherlock Holmes at the 1902 Test by Stanley Shaw. Other people have decided that they want to bring cricket into Holmes in a way that Doyle didn't.

So, what do you think? Should a Sherlock Holmes episode of Shedunnit be something I work towards? Is there anything that I can add to the already-vast canon of Sherlockian thought? I will, as ever, value your input here.

Until next time,

Caroline

You can listen to every episode of Shedunnit at shedunnitshow.com or on all major podcast apps. Selected episodes are available on BBC Sounds. There are also transcripts of all episodes on the website. The podcast is now newsletter-only — we're not updating social media — so if you'd like to spread the word about the show consider forwarding this email to a mystery-loving friend with the addition of a personal recommendation. Links to Blackwell’s are affiliate links, meaning that the podcast receives a small commission when you purchase a book there (the price remains the same for you).

Dear listeners,

There are many, many things that I love about interwar detective fiction — I wouldn't have been doing a podcast about it for coming up to seven years otherwise — but one of my favourite aspects is its variety. The sheer number of different authors, plots, settings and styles never ceases to amaze and delight me. The fact that this one genre and period unites books as different as, say, And Then There Were None by Agatha Christie and Mystery in the Channel by Freeman Wills Crofts is both weird and wonderful.

I'll take any excuse to explore this vast literary terrain. And today's new episode gives me the best possible reason to do so: listeners wanting book recommendations! I've brought back the Murder Mystery Hotline from 2023 and it's open to new calls.

Once again, members of the Shedunnit Book Club provided a wide variety of interesting requests. For their prompts, I went looking for mysteries set in lighthouses and in Ireland, as well as ones that involved Chinese artefacts and Easter chocolates. Along the way, I learned fascinating things about Norwegian crime fiction publishing traditions and the career of Irish writer Sheila Pim, among many other things. I got to read a play by Wilkie Collins, a photographically illustrated short story by Rex Stout and multiple tales involving vanishing harps. Truly, this was one of the most fun reading lists for an episode I've ever had.

And if you'd like to be able to submit a request for a future murder mystery hotline episode, become a member of the Shedunnit Book Club today. As well as the chance to take part in episodes like this, members get ad free episodes, extra audio content and access to a marvellous community that reads a different murder mystery together every month. We are currently reading  Lady Molly of Scotland Yard by Baroness Orczy, a slightly pre-golden age story collection, and I'd love for you to join us in time to discuss it together at the end of the month.

Before I go, here is a picture of Morris the dog swimming around a lighthouse near where we live:

Until next time,

Caroline

You can listen to every episode of Shedunnit at shedunnitshow.com or on all major podcast apps. Selected episodes are available on BBC Sounds. There are also transcripts of all episodes on the website. The podcast is now newsletter-only — we're not updating social media — so if you'd like to spread the word about the show consider forwarding this email to a mystery-loving friend with the addition of a personal recommendation.