Agatha Christie’s Murder in the Making: Stories and Secrets from Her Archive - includes an unseen Miss Marple Story

The cipher/code-letter

The hypodermic syringe and the knockout drops

The comparison of cigarette butts.

Ronald Knox’s Detective Story Decalogue

Monsignor Ronald Knox (1888–1957) was a priest and classical scholar who wrote six detective novels between 1925 and 1937. He created the insurance investigator detective Miles Bredon, and considered the detective story such a serious game between writer and reader that in some of his novels he provided page references to his clues. When he edited a collection of short stories, The Best Detective Stories of 1928, his Introduction included a ‘Detective Story Decalogue’. These distilled the essence of a detective story, as distinct from the thriller, into ten cogent sentences:

1 The criminal must be someone mentioned in the early part of the story, but must not be anyone whose thoughts the reader has been allowed to follow.

2 All supernatural agencies are ruled out as a matter of course.

3 Not more than one secret room or passage is allowable.

4 No hitherto undiscovered poisons may be used, nor any appliance which will need long scientific explanation at the end.

5 No Chinamen must figure in the story.

6 No accident must ever help the detective, nor must he ever have an unaccountable intuition that proves to be right.

7 The detective must not himself commit the crime.

8 The detective must not light on any clues that are not instantly disclosed to the reader.

9 The stupid friend of the detective, the Watson, must not conceal any thoughts that pass through his mind; his intelligence must be slightly, but very slightly, below that of the average reader.

10 Twin brothers, and doubles generally, must not appear unless we have been duly prepared for them.

But as will be seen from a survey of Christie’s output, many of the Rules laid down by both Knox and Van Dine were ingeniously ignored and often gleefully broken by the Queen of Crime. Her infringement was, in most cases, instinctive rather than premeditated; and her skill was such that she managed to do so while still remaining faithful to the basic tenets of detective fiction.

Agatha Christie’s Rule of Three

In order to examine these Rules, and Christie’s approach to them, I have grouped together Rules common to both lists and have divided them into categories:

Fairness

The crime

The detective

The murderer

The murder method

To be avoided

Fairness

Both lists are very concerned with Fairness to the reader in the provision of information necessary to the solution, and with good reason; this is the essence of detective fiction and the element that distinguishes it from other branches of crime writing. Van Dine 1 and Knox 8 are, essentially, the same rule while Van Dine 2, 5, 15 and Knox 9 elaborate this concept.

Van Dine 1. The reader must have equal opportunity with the detective for solving the mystery.

Knox 8. The detective must not light on any clues that are not instantly disclosed to the reader.

Christie did not break these essentially identical rules, mainly because she did not need to. She was quite happy to provide the clue, firm in the knowledge that, in the words of her great contemporary R. Austin Freeman, ‘the reader would mislead himself’. After all, how many readers will properly interpret the clue of the torn letter in Lord Edgware Dies, or the bottle of nail polish in Death on the Nile, or the ‘shepherd, not the shepherdess’ in A Murder is Announced? Or who will correctly appreciate the significance of the smashed bottle in Evil under the Sun, or the initialled handkerchief in Murder on the Orient Express, or the smell of turpentine in After the Funeral?

Knox 9. The stupid friend of the detective, the Watson, must not conceal any thoughts that pass through his mind; his intelligence must be slightly, but very slightly, below that of the average reader.

Hastings has been dubbed ‘the stupidest of Watsons’ and there are times when we wonder how Poirot endured his intellectual company. And, of course, Agatha Christie herself tired of him and banished him to Argentina in 1937 after Dumb Witness, although he was to return for Curtain: Poirot’s Last Case, written during the Second World War but not published until 1975. It can be argued that the intelligence of the Watson character has to be below average because it is necessary for the Great Detective to explain his deductions to the reader through the Watson character. If the Watson were as clever as the detective there would be no need for an explanation at all. If Poirot were to look at the scene of the crime and announce, ‘We must look for a left-handed female from Scotland with red hair and a limp,’ and Hastings were to reply, ‘Yes, I see what you mean,’ the reader would feel, justifiably, more than a little exasperated. And, of course, this Rule overlaps with Knox 1 (see below) in the case of The Murder of Roger Ackroyd because Dr Sheppard in that famous case was acting as Poirot’s Watson.

Van Dine 2. No willful tricks or deceptions may be placed on the reader other than those played by the criminal on the detective.

This Rule seems to negate the whole purpose of a good detective novel. Surely the challenge is the struggle between reader and writer. In essence, the writer says: ‘I present you with a challenge to spot the culprit before I am ready to reveal him/her. To make it easier for you, I will give you hints and clues along the way but I still defy you to anticipate my solution. However, I give you fair warning that I will use every trick in my writer’s repertoire to fool you but I still promise to abide by the fair play rule.’ As Dorothy L. Sayers said in the aftermath of the Roger Ackroyd controversy, ‘It is the reader’s business to suspect everybody.’

Into this category come Christie’s greatest conjuring tricks, including The Murder of Roger Ackroyd and Endless Night. In both these novels the reader is fooled into accepting the bona fides of a character who is taken for granted but not ‘seen’ in the same way that all the other protagonists are. The narrator is a ‘given’ whose presence and veracity the reader accepts unquestioningly. And, indeed, the narrator’s veracity in each case is above reproach. They do not actually lie at any stage. There are certainly some ambiguous statements and judicious omissions but their significance is obvious only on a re-reading, when the secret is known. In Chapter 27 of The Murder of Roger Ackroyd Dr Sheppard himself states:

I am rather pleased with myself as a writer. What could be neater, for instance, than the following? ‘The letters were brought in at twenty minutes to nine. It was just on ten minutes to nine when I left him, the letter still unread. I hesitated with my hand on the door-handle, looking back and wondering if there was anything I had left undone.’ All true, you see. But suppose I had put a row of stars after that first sentence! Would somebody then have wondered what exactly happened in that blank ten minutes?

All true; but not one reader in a thousand will stop to examine the details, especially not in the more innocent era of the 1920s, when the local doctor had a status just below that of the Creator.

Michael Rogers, in Endless Night, is also scrupulously fair in his account of his life. He tells us the truth but, as with Dr Sheppard, not the whole truth. But if we re-read Chapter 6, which recounts a telling conversation with his mother about ‘his plan’, what a new significance it all takes on when we know the truth. The ‘plan’, and even ‘the girl’, are no longer what we had originally supposed. This novel has much in common with The Mysterious Affair at Styles and Death on the Nile, as well as with The Man in the Brown Suit and The Murder of Roger Ackroyd. In the first two titles, two lovers collude, as in Endless Night, in the murder of an inconvenient wife, stage a dramatic quarrel and have seemingly foolproof alibis; The Mysterious Affair at Styles also features a poisoning which happens in the absence of the conspirators. In the latter two titles, the narrator (a diarist in The Man in the Brown Suit) is exposed as the villain.

Van Dine 5. The culprit must be determined by logical deduction – not by accident, coincidence or unmotivated confession.

An example of confession (albeit not unmotivated) as a solution in Christie’s output is And Then There Were None. Here the entire explanation is given in the form of a confession. In this most ingenious novel, Agatha Christie set herself an almost insoluble problem – how to kill off the entire ten characters of the book and yet have an explanation at the end. The only solution would seem to be the one that she actually adopted – a confession. Confessions do feature in other novels, for example Lord Edgware Dies, Why Didn’t They Ask Evans? and Crooked House, but only as confirmation of what has already been revealed, while Curtain: Poirot’s Last Case contains one of the most shocking confessions in literary history …

Van Dine 15. The truth of the problem must be at all times apparent – provided the reader is shrewd enough to see it.

Although tautological, this is intended as an elaboration of the earlier Rules regarding fairness to the reader. One of the clearest examples of this in the Christie output is Lord Edgware Dies where a very audacious plot is, in retrospect, glaringly obvious with all the clues staring the reader in the face. Other blindingly evident clues include the final words – ‘Evil Eye … Eye … Eye …’ – of Chapter 23 of A Caribbean Mystery; or the description of Lewis Serrocold emerging from the study in Chapter 7 of They Do It with Mirrors; or the thoughts of Ruth Lessing in Chapter 2 of Sparkling Cyanide after her meeting with Victor; or, most controversially of all, Dr Sheppard’s leave-taking of Roger Ackroyd in Chapter 4 of The Murder of Roger Ackroyd.

Knox 6. No accident must ever help the detective, nor must he ever have an unaccountable intuition that proves to be right.

There are, unfortunately, a few examples in Christie’s oeuvre of ‘deductions’ not based on any tangible evidence. It must be conceded that they can only be accounted for by intuition. How, for example, does Miss Marple alight on Dr Quimper in 4.50 from Paddington? And only the ‘Divine Revelation’ forbidden by The Detection Club Oath can explain how Poirot knows that Lady Westholme from Appointment with Death spent time in prison in her early life.

The crime

The crime itself did not feature strongly in the Rules, although Christie enjoyed the challenge of Van Dine 18 below.

Van Dine 7. There simply must be a corpse in a detective novel.

The first detective novel, Wilkie Collins’ The Moonstone (1878), concerns a robbery rather than a murder, but a mysterious death is the sine qua non of most detective novels. Although she broke this Rule often in her short story output, Christie never short-changed her readers in novel form, generously providing a multitude of corpses in And Then There Were None, Death Comes as the End and Endless Night.

Van Dine 18. A crime in a detective story must never turn out to be an accident or a suicide.

The rejection of this Rule could mean a huge disappointment for a reader who discovers, after 250 pages, that the death under investigation is not a crime at all. See how cleverly Agatha Christie overcomes this. In Taken at the Flood, none of the deaths is what it first seems. The seeming murder of ‘Enoch Arden’ is an accident, the death of Major Porter is suicide and the seeming suicide of Rosaleen Cloade is murder. In one brilliant plot she effortlessly breaks both aspects of Van Dine’s Rule. In the Poirot cases ‘The Market Basing Mystery’ and ‘Murder in the Mews’ – both essentially the same story, the latter being a more elaborate version, 15 years later, of the former – we have not murder disguised to look like suicide but suicide disguised to look like murder. But there is another twist; the real murder plan is to get someone else hanged (and therefore murdered) for a crime they did not commit. Both suicide scenes are subtly altered to give an impression exactly opposite to the reality.

Van Dine 19. The motives for all the crimes in detective stories should be personal.