At first sight, Poe's short story "The Purloined Letter" presents itself as a simple and hardly complex detective tale. Its style, thus, reminds of an anecdote or even of a joke that is being told with the plot building up to a punch line at the very end of the story. When taking a closer look and with a little reading between the lines, however, the story can be seen as a guideline to detective fiction in general and a tutorial on how to discover the solutions to occurring mysteries.
Poe's characters appear to be summarising the overall scheme of the detective fiction genre: Dupin characterises the problem the Prefect is faced with as being "Simple and odd". The basic situations of a detective tale are often of a criminal and very striking nature, be it murder, theft or things alike. Surrounding these events is an aura of the absurd or puzzling, something that makes the case at hand unusual and worth examining.
For the reader who is interested in digging into the fundamentals of the plot, discovering who committed the crime or what may be the hidden clue to solve the mystery is an essential and entertaining part of detective fiction. Dupin, again, gives a hint on how to untangle the woven net of clues. Like the Prefect, a lot of readers tend to think way off the track. While the Prefect has his men practically dismantle complete houses including their surroundings instead of looking in the closest and most obvious spots, the audience seems to be misguiding themselves through increased expectations. The riddles will not always be solved by looking for cavities carved into wooden bedposts, likewise, the riddles will sometimes be solved by focusing the attention to the most apparent solutions.
Like the boy at a game of "even and odd" or like Dupin with his adversary Minister D, the reader should be aware of the "opponent's" (the story in question) quality. Different qualities of writing demand for different strategies of reading: a plain and simple story demands very little of the reader, the solutions may, therefore, be close at hand. More complex stories can contain foreboded twists and truly tense forms of detective writing can afford leaving the most obvious solution to a riddle undiscovered by the reader due to doing what all good magicians do: lure the audience's attention away from the point of action.
Poe manages to completely summarize the methods of detective fiction wrapped up in a detective tale of his own. He even includes some advice for his readers and readers in general on how to deal with this literary genre and makes reading even more enjoyable and less frustrating for those who wish to occasionally play detective for themselves while reading.
