- The Murders in the Rue Morgue (1841),
- The Mystery of Marie Rogêt (1842), and
- The Purloined Letter (1844).
The first is perhaps the most dramatic and most famous. It has been filmed around a half dozen times. The latter two, once.
Nonetheless, the most iconic, I contend, is the lattermost. It brought forth the idea [Note: I am about to deliver the dreaded spoiler, so read the tale now before your mind is forever corrupted] of hiding things in plain sight. The actual story isn't as simple as the concept it delivers. Dupin points out that 1) the astute can guess behavior patterns of people based on their intelligence, 2) you can make gains in politics through the destruction of another's morality (a lesson still in practice--perhaps more popular than ever), and 3) hiding things in plain sight... through simple disfigurement, while hanging with other items of similar disfigurement.
Paul Collins, a biographer of Poe, calls these essays. And they are--of a fictionalized sort--especially "The Purloined Letter". Dupin spends a great deal of time reasoning out all the extraneous matter and beating around to his final point. In the modern locked-room mystery, Dupin's stories represent the final unraveling, where the detective relates how the mystery occurred. His methods are similar to Doyle's Sherlock Holmes's. Doyle also employs a sidekick like Dupin who can become our proxy for our awe of the detective's mental prowess.
Doyle's sidekick, Watson, is superior in that he actually has a personality that develops across the stories. Poe's is an anonymous blank-slate. Even Dupin is something as a blank slate except for one thing: He talks a lot, demonstrating his genius.
If Dupin were real, some people would become enthralled and hang on in his every word. Most would probably lose track of what he was saying and think of other matters, waiting for him to finish what he had to say, stifling yawns and glancing at pocket watches: "My! Look at the time." I think the term "blowhard" is unfair as he is just explaining a crime at length, but that would likely be the feeling that most people would got in his presence, especially if they feared intellectual matters that shot over their heads.
According to Collins, Poe wrote literary puzzles for readers to figure out. I suspect that these Dupin stories were an outgrowth of such interest, exploring dramatic puzzles of crime. The idea of Dupin's character may never have come to mind. For all that Dupin might have been a pain to be around in real life, his reasoning has been fascinating to read for nearly 175 years.