The Purloined Letter
Research papers on Edgar Allen Poe point out that the most significant of the Dupin detective fiction stories is The Purloined Letter, written in 1844. In The Purloined Letter, an untrustworthy clergyman pilfers a letter from the Queen in her presence. Many term papers on The Purloined Letter show how writers of detective and mystery fiction have employed the technique of concealment in plain sight since Edgar Allen Poe developed it in Poe's detective fiction.
The Purloined Letter research paper points out that it is partly a piece of short fiction and partly expository prose. In terms of the fictional plot, the success of the protagonist, Dupin, in obtaining the letter in D—‘s possession—and thereby inflicting revenge upon him—is a function of the “truths” expressed in his own, occasionally interrupted, rambling monologue, a monologue that is a mini-essay dealing with, among other things, two interesting themes. The first of these is epistemological; it is Dupin’s theory of knowledge in The Purloined Letter. The second is psychological; Dupin’s theory of human perception in The Purloined Letter. Dupin denigrates the theory that mathematical knowledge is that form of knowledge that is most certain. There is, he says, something higher, the “abstractly logical.” This is open not to the mathematician, but to the poet. Dupin states of D--, “As poet and mathematician, he would reason well; as poet, profoundly; as mere mathematician he could not have reasoned at all….”
As a poet himself Dupin is capable of reasoning out the way in which D— would attempt to conceal the letter; he would “conceal” it by leaving it in the open. Any attempt at concealment would be detected by the searching police, but because people tend to perceive things in a certain way, because they tend not to see the forest for the trees, leaving it in the open will cause it to fail to be noticed. There is, Dupin says, “a moral inapprehension by which the intellect suffers to pass unnoticed those considerations which are too obtrusively and too palpably self-evident.” There is also, Dupin says, something analogous to this with the act of physical perception itself. It is this knowledge that Dupin uses to get the letter.