Edgar Allan Poe wrote three stories about C. Auguste Dupin; this was the first one. Each of the Dupin stories contains essentially the same theme: the triumph of analytical reasoning over mere thinking. Again and again in “The Murders in the Rue Morgue,” Poe, through the assertions of Dupin, makes invidious comparisons between the crime-solving methods of the police and the analytical powers of the highly trained mind. In this tale, it is necessary that the gifted Dupin visit the scene of the crime and make careful observations of the physical evidence in order to draw his conclusions. It is not always necessary, however, for the amateur detective to be on the scene, because most of what he accomplishes he achieves by careful analysis of the facts in the case.
In this story, the now classic locked-room mystery is introduced for the first time. Moreover, Poe created here the first detective story in American literature. In so doing, he also created the basic template that later writers in England and the United States would use to build their detective heroes. Thus, it was with the publication of this tale that Poe became the father of the detective story.
An important thematic element in this story is the use of reason as a kind of defense against unreason, of rationality against irrationality. The horror of the murders in the Rue Morgue disturbs the little universe of the neighborhood; Dupin’s application of reason to the problem restores order. Thus, Poe, through the medium of this and other of his detective stories, seems to be arguing that reason is humanity’s most potent weapon against acts of madness. However, because Dupin is depicted as an extraordinary human being whose behavior and analytical powers mark him as an outsider, it would seem that, for Poe, the forces of reason may be overcome in the long run.