Although Poe is credited with the creation of the detective story and the character type known as the amateur sleuth, obviously Auguste Dupin and his ratiocinative ability did not spring from nowhere. Probably the two most obvious sources are Voltaire's Zadig (1748) and Eugene Francois Vidocq's Memoirs of Vidocq, Principal Agent of the French Police (1828-29). Poe probably knew the story of Zadig's being able to deduce the description of the King's horse and the Queen's dog by examining tracks left on the ground and hair left on bushes. He also mentions Vidocq, the first real-life detective, in "Murders of the Rue Morgue" as a "good guesser."

However, Poe's creation of the ratiocinative story also derives from broader and more basic interests and sources. In several of his most famous critical essays, such as his 1842 review of Nathaniel Hawthorne's Twice-Told Tales and his theoretical articles, "Philosophy of...