This story, like "The Murders in the Rue-Morgue," concerns Dupin, and the period of time that the narrator of "The Purloined Letter" spent with him in Paris. One evening, the Prefect of the police calls at their apartment. The pair invite him in. The narrator admits the Prefect is as entertaining as he is annoying.
Dupin's superior but eccentric crime-solving intelligence was made clear from The Murders in the Rue Morgue, so when the Prefect calls the apartment, it is clear that another mystery story of a sort is on tap. It’s clear that he chief of police somewhat relies on this rogue detective.
They light a candle but when the Prefect announces that he comes on official business and needs help with a case, Dupin extinguishes the light. It’s another of his fancies that good thinking is better done in the dark. The Prefect explains that, while the case he comes to them about is very simple, it is also very odd, which is why it might interest Dupin.
Dupin’s analytical intelligence, as indicated when he turns off the light, is associated with darkness. He is not someone who follows straight, simple reason. He is a poet and a mathematician. His reason is one of indirection, of thinking through sensibility and intuition, of darkness.
In fact the case is so simple that its resistance to solution has the police very confused. Dupin suggests that its very simplicity might be what’s causing their trouble. The Prefect finds this idea hilarious. When he stops laughing he agrees to tell them the situation, if they swear secrecy. He goes on to explain that an important document has been “purloined” from the royal apartments.
The Prefect then cryptically suggests that he knows that the person that stole the letter still has it, because of a certain lack of fallout that would definitely occur had the letter passed out of the robber’s hands. The letter, he says, has the power to bring scandal to a certain person of high honor and give the person with the letter great power. The Prefect reveals that the thief is a Minister, who snuck into the royal bedroom and accosted the royal lady and seeing the contents of the letter, blackmailed her. He then stole the letter, in her full view, and replaced it with his own replica document. Dupin notes that because the royal lady is aware of the theft it gives the thief power over her. The Prefect confirms that the thief has been using this power. Helpless, the lady has come to the Prefect desperate for help.
Poe paints a world of corrupt royal hierarchies and abuses of power. The Prefect, who is considered thorough but simple and uncreative, is in charge of the safety of the most high profile figures in the country. The Minister, who should be protecting the royal family, is seeking to use them for his own ends. And the man who can solve the case is Dupin, an eccentric poet.
The Prefect explains what has been done so far in the investigation, and Dupin comments on the police’s habitual thorough investigations. The prefect says it was necessary to search the Minister’s apartment, and this could be quite conveniently done because of the Minister’s frequent absence at night, and because the prefect is in possession of a master set of keys for the city’s properties. He has therefore been engaged in this search for three months, refusing to quit – a handsome reward awaits the finder of the letter.
The police attack the case head on. They search the apartment, over and over, more and more carefully, refusing to quit. The police are living up to Dupin’s criticism and the narrator’s introductory description of the methodical but uncreative mind.
the narrator of "The Purloined Letter" asserts that it might be possible for the letter to be hidden somewhere other than the Minister’s apartment but the prefect is sure that it is not, because the letter holder’s power depends on being able to destroy it at a moment’s notice. The narrator assumes that the minister is not carrying it with him, and the prefect admits that the police have already stopped and searched him.
The prefect seems to be in possession of every advantage in this case. Not only is the Minister conveniently absent for long portions of the day but the police are also given ample opportunity to search the man himself. And yet they can find nothing.
Dupin thinks they should have known that the Minister would be too clever not to expect to be stopped and searched. The prefect says that though the minister is not a fool, he is a poet, which is a very similar thing. Dupin admits that he too is a bit of a poet.
The Prefect’s idea of poetry being equal to foolishness is a significant misconception that bothers Dupin – whose revered intelligence is said to be both poetic and mathematical, just like the Minister (establishing the minister as a kind of double to Dupin).
The prefect describes his method of investigation, how he looked over every inch of the apartment. He knows very well how to uncover “secret” spaces, like parts of drawers blocked off, and chair legs that have been hollowed and stuffed with wadding so that the wood seems to have the same density. They studied every rung in the hotel with a microscope to detect any hint of dust, and then the bedclothes and every item of furnishings, and then scrutinized the walls and surfaces of the house in the same way. They did this not just to the minister’s building but to the two adjoining buildings too, and the paved grounds.
The police have searched literally every square inch of the Minister’s apartment. The long description of each process in the search goes into microscopic detail. The direct and systematic way that the police are able to carry out their search removes the story for a moment from the idea of crime – danger seems far away.
The narrator of "The Purloined Letter" is astonished, but the prefect again reminds him of the large reward. The narrator asks if he checked every single document in the minister’s library, and the prefect assures him that they did, and not only that, they checked between every single page of every volume. When the prefect is done with his exhaustive list of investigated areas, the narrator thinks that it must follow that the letter is not after all within the apartment. The prefect agrees. He now asks Dupin for advice but all Dupin can say is to search the apartment again. He asks if the prefect has a description of the letter itself, and the prefect eagerly gives one in minute detail from a notebook. He then leaves, feeling at a loss about the whole case.
At this point the prefect needs Dupin to give him advice but Dupin only tells the prefect to keep doing what the police have already unsuccessfully tried. Knowing how superior Dupin’s analytical mind is, his dismissal of the prefect with so simple a suggestion shows the humorous side of Poe’s detective story.
The prefect returns the following month and, when asked about the purloined letter, is disappointed to admit no further developments. He made another thorough search but found nothing. Dupin asks how much the reward is and the prefect says that he will personally pay fifty thousand francs to anyone who can bring him the letter. Dupin suggests that there are still further avenues of investigation to go down, and mentions a man called Abernathy, a physician, who, when asked by a miser what to take for a hypothetical condition, told him to “take advice”.
Dupin is completely in charge of this situation. Even though he gave the prefect lousy advice the last time, the prefect returns, showing how dependent he is on Dupin. Dupin’s response is cryptic and condescending.
The prefect disregards Dupin’s story but says that he is serious about the reward. Dupin then calmly asks the prefect to write him a check, and when he has it, he will hand over the letter. The narrator of "The Purloined Letter" and the prefect are in shock at this turn of events. The prefect writes the check for fifty thousand francs, and Dupin, true to his word, produces the letter. The prefect is overjoyed and rushes off immediately.
Though Dupin’s manner seems silly and mysterious, the prefect trusts him, and writes him the requested check without questioning his methods. Dupin shows his creative intelligence by understanding and predicting the prefect’s behavior as well as the Minister’s.
Dupin then explains himself to the narrator of "The Purloined Letter". He says that he had faith that the police would do a completely thorough search of the apartment, as far as their methods allowed. But this method is not suited to the criminal in question – the prefect has been both too shallow and too deep in his search. Dupin gives an example to illustrate his point. He reminds the narrator of a schoolboy game, where one boy conceals marbles in his hand, and the other must guess whether it is an even or odd number of marbles. One boy that Dupin once knew was a master of this game because he knew how to predict the other boys’ behavior according to their intellect. The boy claimed that he mimicked the other boy’s expression and in doing so, found a natural kind of sympathy for the boy’s thoughts and intentions. Dupin compares the schoolboy to famous thinkers like Machiavelli.
One of the most unlikely and intimidating factors of Dupin’s intelligence is his understanding of many different kinds of people, to the extent that he seems to inhabit their minds. But his sympathies also allow him to see genius in unlikely places, this child on the school playground for example. This sensitivity to displays of intelligence in many walks of life is significant in making Dupin seem more human.
So, the accuracy of the guess depends on the accuracy with which the opponent is judged. Dupin says that the police only think about what they would have done in the situation, where they would have hidden the letter, and this is only accurate of a kind of average, Prefect-like intelligence and not of the more unusual kind of the Minister. Their problem is they never adjust their approach, they only exaggerate it, as they did by searching the house over again. By assuming that the letter can be found by something as basic as searching, they are completely disregarding the acumen of the criminal.
There is something about the mind of a criminal and minds themselves that fascinates Dupin. This passion and his unusual sensitivity and sympathy for other minds makes him an intimidating character, because he fills neither the role of detective nor the role of criminal, but somewhere in between or both at once.
The Prefect’s short sightedness is also down to his perception of the Minister as a fool, because he is a poet. All fools are poets, says Dupin, but it does not necessarily follow that all poets are fools. The narrator remembers that the minister is a renowned mathematician and wonders if Dupin has misattributed the title of poet, but Dupin claims he knows the man well, and he is both mathematician and poet. If he were only a mathematician, he wouldn’t have been able to reason so well, says Dupin. The narrator of "The Purloined Letter" thinks this is a strange theory. It is completely contrary to popular opinion about mathematics. But Dupin responds with a French phrase about how inconsequential an idea’s popularity is.
This is an interesting part of Dupin’s character. His identification as a poet and a mathematician as well as his obvious ability to tell a good story and create suspense likens him convincingly to Poe himself. The concept of poetry and methodology is what makes up a successful horror story, whose plot must be flawless but creative enough to deceive.
Dupin explains that he finds fault with forms of thinking that are not abstractly logical. He thinks math is only concerned with shapes and quantities, which are truths of the relation of one thing to another, rather than the true quality of things. In a book called ‘Mythology’, the author discusses the phenomenon where myths are remembered and referred to as if they are real. And the mathematician does this with the theories and equations he holds true, and will listen to no other mode of thought.
Dupin summons the arenas of poetry and mathematics, the scope of mythology and the detail of geometry, so that the range of his knowledge seems limitless. And unlike many other figures of influence in Poe’s Gothic stories, Dupin’s knowledge has been gained by worldly means, reading widely and learning, which makes an interesting contrast to the paranormal side of traditional Gothic literature.
Dupin returns to the Minister. He knows that, because the minister has fooled the Prefect, he has the abilities of a poet as well as a mathematician, and understood everything that the police were likely to do in response to his crime. Dupin believes that his absences from the apartment were deliberate, and that he knew the prefect’s train of thought and knew to avoid any kind of concealment of the letter.
Dupin’s understanding of the Minister’s techniques shows that he understands the mind of a criminal, which gives him a certain threatening power which he wields throughout the story, just like in Murders in the Rue Morgue. We are made aware that Dupin could probably quite easily commit some crimes himself.
Dupin reminds the narrator of "The Purloined Letter" what he said to the prefect when he visited, about the riddle being too self-evident. He believes that the material world and the metaphorical world are strongly connected. He uses two examples. The first is the principle of inertia being the equal in physics and metaphysics. The second is a game where one player asks another player to find a name on a map, and the clever player will choose an overarching county name or some other broad term that is stretched across the map or placed high up on a sign. Most people expect that the many-lettered, or obscure names will be most difficult to find, but it is often the simplest answer that can be overlooked, just like the case of the purloined letter.
Dupin displays his skill in this speech. He shows us how he is able to consider deep concepts and human observations at the same time, and consider many dimensions and levels of meaning at once. While thinking of the academic realm of metaphysics, he also conjures a simple image of a map and the visual effect of the important names of counties and so on being spread across the terrain.
The more Dupin considered the intelligence of the Minister, the more he believed that the best way he could invent of concealing the object beyond the scope of the prefect’s usual search, but also to keep it handy so he could destroy it at a moment’s notice, was to not conceal it at all. With this idea, Dupin says that he went to the Minister’s apartment himself, and performed his own search.
Even the most obvious deception fools the police. In fact, the best way to fool them is not to hide anything, to expose the crime completely. This makes the police force seem laughable and Dupin, with his own agenda, takes the lead by himself.
Dupin mentions that if you saw the Minister at home, you’d think him one of the laziest men in the world, despite his reputation for being energetic. Dupin, wearing dark glasses so that he could look freely about the apartment, searched the documents lying about, and then noticed a card rack, with several letters in, one of which was very crumpled and used, with the Minister’s seal on it. Dupin knew this was the famous letter, even though it differed so radically from the one the Prefect described. In fact, it looked so much like a deliberate ploy to mislead, that Dupin was sure that the Minister had fashioned it to dupe the police, whose methods he knew to be both shallow and thorough enough to overlook such a clue. Dupin stayed for a long time, pretending to be engrossed in conversation, and saw that the letter’s edges were chafed – he could tell that the letter had been turned inside out, and resealed.
It is humorous how opposite Poe has made the two searches, the police search and Dupin’s, of this apartment. The police searched for months on end, every chair rung and bed sheet, while Dupin enters the room and within an hour or so spots the letter. This shows how in line Dupin’s mind and the Minister D___’s mind are. It furthers the notion that they are rivals or in fact doubles. But though they share the same kind of intelligence, Dupin is coming out on top – he is able to see the Minister’s tricks before the Minister realizes that Dupin is investigating.
Dupin purposely left a gold snuff box on the Minister’s table so that he could return to retrieve it the next day. During this second visit, their conversation is interrupted by the sound of a pistol shot and frightened voices, which of course draws the Minister to the window. Dupin takes his opportunity to take the letter and replace it with a replica he had prepared. He explains that he had planted the gunman outside to create a distraction for just this purpose.
Dupin uses indirection to trick the Minister, who was himself a master of indirection. Dupin bests his rival.
The narrator of "The Purloined Letter" is unclear why Dupin replaced the letter, rather than just stealing it. Dupin explains that the Minister is a bold man with a lot of support around him, so he may have killed him if he learned the truth. Also, Dupin is eager to get revenge for the royal lady, by transferring the political power to her – this can only be done if the Minister is unaware that he no longer possesses it. Dupin comments that it’s a popular view to think that it is easy to fall into moral ruin, but he has no pity for the fallen.
Dupin’s motivations come into focus in this part. His goal is not so much justice as it is a quest for revenge and success. It is difficult to sort him into a category of good or bad. His morality seems to follow his analytical mind, he favors sense and rationality but also his emotions.
Dupin is, however, curious to know how the Minister will react to the replacement letter, which he filled with a message. He explains now that the minister once personally wronged him and he had warned him at the time that he would remember it. So, wanting to give the minister a clue as to his identity, he wrote a single phrase on the letter, “Un dessein si funeste, S'il n'est digne d'Atree, est digne de Thyeste,” which translates to “So baneful a scheme, if not worthy of Atreus, is worthy of Thyestes.” This is from a story by Crebillon about a pair of brothers, who both wrong each other.
Dupin at first appears like an unbeatable detective, looking out for the justice of the city and enjoying the logic puzzle of the crime scene, but now he appears to have a bias too. His personal history is tied up in this crime. In the note Dupin leaves is a reminder that Dupin is a mathematician and a poet. This final act shows his poetic side – he solves the crime with style and, in his note, places himself in a club of literary of characters.