Agatha Christie’s Complete Secret Notebooks. Агата Кристи

who, by logical deduction, arrives at a most unexpected solution, thereby proving the innocence of an arrested man; the story is narrated by his unnamed associate.

      Although Poe is not one of the writers she mentions in An Autobiography as being an influence, Agatha Christie took his template of a murder and its investigation when she began to write The Mysterious Affair at Styles, 75 years later.

       The brilliant amateur detective

      If we take ‘amateur’ to mean someone outside the official police force, then Hercule Poirot is the pre-eminent example. With the creation of Miss Marple, Christie remains the only writer to create two famous detective figures. Although not as well known, the characters Tommy and Tuppence, Parker Pyne, Mr Satterthwaite and Mr Quin also come into this category.

       The less-than-brilliant narrator-friend

      Poirot’s early chronicler, Captain Arthur Hastings, appeared in nine novels (if we include the 1927 episodic novel The Big Four) and 26 short stories. After Dumb Witness in 1937, Christie dispensed with his services, though she allowed him a nostalgic swan song in Curtain, published in 1975. But she also experimented with other narrators, often with dramatic results: The Man in the Brown Suit, The Murder of Roger Ackroyd, Endless Night. The decision to send Hastings to Argentina may have had less to do with his mental ability than with the restrictions he imposed on his creator: his narration meant that only events at which he was present could be recounted. Signs of this growing unease can be seen in the use of third-person narrative at the beginning of Dumb Witness and intermittently throughout The ABC Murders, published the year before Hastings’ banishment. Miss Marple has no permanent Hastings-like companion.

       The wrongly suspected person

      This is the basis of some of Christie’s finest titles, among them the novels Five Little Pigs, Sad Cypress, Mrs McGinty’s Dead and Ordeal by Innocence, and the short story ‘The Witness for the Prosecution’. The wrongly suspected may be still on trial as in Sad Cypress or already convicted as in Mrs McGinty’s Dead. In more extreme cases – Five Little Pigs, Ordeal by Innocence – they have already paid the ultimate price, although in each case ill-health, rather than the hangman, is the cause of death. And being Agatha Christie, she also played a variation on this theme in ‘The Witness for the Prosecution’ when the accused suspect is shown to be the guilty party after all.

       The sealed room

      The fascination with this ploy lies in the seeming impossibility of the crime. Not only has the detective – and the reader – to work out ‘Who’ but also ‘How’. The crime may be committed in a room with all the doors and windows locked from the inside, making the murderer’s escape seemingly impossible; or in a room that is under constant observation; or the corpse may be discovered in a garden of unmarked snow or on a beach of unmarked sand. Although this was not a favourite Christie ploy she experimented with it on a few occasions, but in each case – Murder in Mesopotamia, Hercule Poirot’s Christmas, ‘Dead Man’s Mirror’, ‘The Dream’ – the sealed-room element was merely an aspect of the story and not its main focus.

       The unexpected solution

      Throughout her career this was the perennial province of Agatha Christie and the novels Murder on the Orient Express, Endless Night and And Then There Were None, as well as the short story ‘The Witness for the Prosecution’, are the more dramatic examples. But mere unexpectedness is not sufficient; it must be fairly clued and prepared. The unmasking of, for example, the under-housemaid’s wheelchair-bound cousin from Australia, of whom the reader has never heard, may be unexpected but it is hardly fair. The unexpected murderer is dealt with below.

       The ‘armchair detective’ and pure reasoning

      In 1842, Poe’s story ‘The Mystery of Marie Roget’ was an example both of ‘faction’, the fictionalisation of a true event, and of ‘armchair detection’, an exercise in pure reasoning. Although set in Paris, the story is actually an account, complete with newspaper reports, of the murder, in New York some years earlier, of Mary Cecilia Rogers. In this story Dupin seeks to arrive at a solution based on close examination of newspaper reports of the relevant facts, without visiting the scene of the crime. The clearest equivalent in Christie is The Thirteen Problems, the collection in which a group of friends, including Miss Marple, meets regularly to solve a series of mysteries including murder, robbery, forgery and smuggling. Miss Marple also solves the murders in The Mirror Crack’d from Side to Side basing her solution on the observations of others, and visiting the scene of the crime only at the conclusion of the book. She undertakes a similar challenge in 4.50 from Paddington when Lucy Eyelesbarrow acts as her eyes and ears. Poirot solves ‘The Mystery of Hunter’s Lodge’, in Poirot Investigates, without leaving his sick-bed; and in The Clocks, making what amounts to a cameo appearance, he bases his deductions on the reports of Colin Lamb. For the novels of Christie’s most prolific and ingenious period (roughly 1930 to 1950), the application of pure reasoning applies. From the mid 1950s onwards there was a loosening of the form – Destination Unknown, Cat among the Pigeons, The Pale Horse, Endless Night – and she wrote fewer formal detective stories. But as late as 1964 and A Caribbean Mystery she was still defying her readers to interpret a daring and blatant clue.

       The interpretation of a code

      Poe’s ‘The Gold Bug’, not a Dupin story, appeared in 1843, and could be considered the least important of his contributions to the detective genre. It involves the solution to a cipher in an effort to find a treasure. A variation on this can be found in the Christie short stories ‘The Case of the Missing Will’ and ‘Strange Jest’, both of which involve the interpretation of a deceased person’s last cryptic wishes. Although the code concept was only a minor part of Christie’s output it is the subject of the short story ‘The Four Suspects’ in The Thirteen Problems. On a more elaborate canvas, the interpretation of a code could be seen as the basis of The ABC Murders; and, more literally, it is the starting-point of Christie’s final novel, Postern of Fate.

       The trail of false clues laid by the murderer

      ‘Thou Art the Man’, published in 1844, is not as well known as the other Poe stories but it includes at least two influential concepts: the trail of false clues and the unmasking of the most unlikely suspect. Although a minor theme in many Christie novels, the idea of a murderer leaving a trail of false clues is a major plot device in The ABC Murders and Murder is Easy; and in Towards Zero it is taken to new heights of triple-bluff ingenuity.

       The unmasking of the least likely suspect

      Like its counterpart above, the unexpected solution, this was a career-long theme for Christie and appears at its most stunning in The Murder of Roger Ackroyd, Hercule Poirot’s Christmas, Crooked House and Curtain. The double-bluff, a regular feature of Christie’s output from her first novel onwards, also comes into this category.

       Psychological deduction

      Poe’s ‘The Purloined Letter’ pioneered the ideas of psychological deduction and the ‘obvious’ solution. In this type of story, the deductions depend as much on knowledge of the human heart as on interpretation of the physical clues. In Poe’s story Dupin’s psychological interpretation of the suspect allows him to deduce the whereabouts