his early impression of the brilliant detective:

“It is simple enough as you explain it,” I said, smiling. “You remind me of Edgar Allen Poe’s Dupin. I had no idea that such individuals did exist outside of stories.”

Holmes’ response to this seemingly complementary comparison is a surprise to Watson, and to the reader, as he summarily rejects any such parallels with a fictional detective:

“. . . in my opinion, Dupin was a very inferior fellow. That trick of his of breaking in on his friends’ thoughts with an apropos remark after a quarter of an hour’s silence is really very showy and superficial. He had some analytical genius, no doubt; but he was by no means such a phenomenon as Poe appeared to imagine.”

Especially with the advantage of hindsight, the reader can better appreciate this introduction to what would become the most famous detective in the history of literature.  While Holmes’ reaction to Watson’s observation is surprisingly hostile, Doyle’s literary debt to Poe is, as noted, fully appreciated.

The similarities between Poe and Conan Doyle, and between Dupin and Holmes, are, nevertheless, striking.  Both employ deductive reasoning to piece together clues and to identify the guilty party.  Both authors were deeply fascinated by the analytics needed to resolve the most complicated of mysteries, and by the role of simple observation in guiding the investigator in question towards the eventual identification of the guilty party. Early in "The Murders in the Rue Morgue," Poe’s narrator, describing the ideal investigative mind, soon to be revealed as Dupin, notes the following:

“To observe attentively is to remember distinctly; and, so far, the concentrative chess-player will do very well at whist; while the rules of Hoyle (themselves based upon the mere mechanism of the game) are sufficiently and generally comprehensible. Thus to have a retentive memory, and to proceed by "the book," are points commonly regarded as the sum total of good playing. But it is in matters beyond the limits of mere rule that the skill of the analyst is evinced. He makes, in silence, a host of observations and inferences. So, perhaps, do his companions; and the difference in the extent of the information obtained, lies not so much in the validity of the inference as in the quality of the observation. The necessary knowledge is that of what to observe.”

In Chapter II of A Study in Scarlet, titled “The Science of Deduction,” Conan Doyle similarly emphasizes the importance of and centrality to his detective’s methodology of deductive reasoning. Watson, appearing at the breakfast table in the home now shared by him and his new friend, Holmes, notices the reading material being closely scrutinized by the detective:

“Its somewhat ambitious title was ‘The Book of Life,’ and it attempted to show how much an observant man might learn by an accurate and systematic examination of all that came in his way. It struck me as being a remarkable mixture of shrewdness and of absurdity. The reasoning was close and intense, but the deductions appeared to me to be far-fetched and exaggerated. The writer claimed by a momentary expression, a twitch of a muscle or a glance of an eye, to fathom a man’s inmost thoughts. Deceit, according to him, was an impossibility in the case of one trained to observation and analysis.”

In short, the main similarities between authors involved the application of deductive reasoning in the furtherance of criminal investigations, with Poe credited with largely inventing the genre and Conan Doyle credited with perfecting it. Conan Doyle’s, though, is a far more voluminous body of work than that of Poe, whose more popular stories involve individuals describing their motivations and actions in conducting murder while strenuously denying the mental deficiencies that those actions most definitely illuminate. Poe’s short stories, such as "The Black Cat," "The Tell-Tale Heart," and "The Fall of the House of Usher," are of a very different literary genre than his three noteworthy efforts at developing the detective story. In this, the distinctions between authors is quite prominent. Conan Doyle developed a series of stories involving a brilliant detective, aided in his investigations by his loyal friend and biographer Dr. John Watson, who will repeatedly be confronted by his evil alter-ego, Professor Moriarty, whose very title suggests an intelligent and cunning adversary. Poe, in contrast, was clearly as influenced in the macabre as he was in the resolution of who killed who.

Poe’s stories, excluding the aforementioned horror tales, are comparable in the sense that they involve mysteries, but, with the exception of those three Dupin stories, he was far less disciplined in constructing his mysteries, paying scant attention to the detailed chain of clues the detective must follow in order to arrive at the appropriate conclusion. Poe was, in short, more eclectic in his vision (whether the ingestion of narcotic substances contributed to this situation is a matter of speculation) and more interested in a wider variety of fictional writing. His detective stories, with the exception of the three Dupin stories, pay less fealty to the conventions of the genre, if only because Poe had just invented that genre.