Poe had an effect on two major literary genres: the short story and the detective/mystery story. From this, his influence rippled out to have an effect on prose literature as a whole.

In 1846, Poe wrote an influential essay called "The Philosophy of Composition." In it, he made two important points. He thought writers should plan their work to highlight the emotional effect they hoped to elicit from readers. For example, if the goal was to generate the emotion of fear, then all the elements of the story from setting to character to plot should be scary. Related to this is the idea of brevity. Poe thought literature should get to the point and not ramble on and on. Both of these elements supported his central idea that a work of writing should be carefully planned with the ending in mind, not simply a rambling response to inspiration.

1846 is a significant date, a time when prose fiction was still evolving and many bloated works (to our modern minds) were being written. Poe helped set the direction for the more streamlined plots and prose that are characteristic of the modern age.

Just as significantly, Poe is credited for establishing the format of the modern detective or mystery story in which a highly talented amateur uses logic and insight to solve a crime that defies the police. Poe's detective Dupin became the prototype for the modern detective from Sherlock Holmes to Hercule Poirot.

Edgar Allan Poe has proven to be a remarkably influential writer, an influence perhaps most powerfully expressed in his role as the originator of the detective story (with his character of C. Auguste Dupin being a direct influence on the later Sherlock Holmes). In addition, Poe has exerted a profound influence on both the horror genre and the crime genre, with his macabre tales centered around often criminally insane villain protagonists. In his focus on the psychologies of his character, as well as in his use of unreliable narrators, Poe did much to enrich literature, while also helping to establish the literary reputation of the short story as an art form.

In addition, however, perhaps his most far reaching and important legacy can be found not in his short stories themselves, but instead in his work as a literary theorist. One of Poe's most important theories lay in his insistence that literature (particularly short literature) needs to be written with a single effect in mind. In short: what experience does the writer wish readers to come away with after reading any given literary work? With this in mind, Poe argued that stories should essentially be planned backwards, beginning with its ending (where, if the story is written well, this effect should be felt the strongest). This approach has proven highly influential in shaping the short story format as it has evolved ever since.

Poe had a very strong influence on Charles Baudelaire, who translated much of Poe's work into English. Baudelaire, whose best-known work is the collection of poems titled Les Fleurs du Mal (Flowers of Evil) actually idolized Poe. The French appreciated Poe more than the Americans. Poe's work in French translation influenced many French writers and subsequently influenced Russian writers like Dostoyevsky, whose novel Crime and Punishment shows the strong influence of Poe. Poe was noted for focusing on the dark side of human nature. He is known as the father of the detective novel, and had a direct influence on Arthur Conan Doyle, creator of Sherlock Holmes. Since then there have been countless thousands of detective novels published all over the world, as well as horror tales. Famous writers who follow in Poe's and Doyle's footsteps are Agatha Christie, George Simenon, and Erle Stanley Gardner. Poe was one of the first authors to write science-fiction stories and might be called the "father of science-fiction." He has also been called "the father of the modern short story." American and English writers were indirectly influenced by Poe via the French. Stephen King is a good example of a modern writer who would probably not have written most of his works if not for the precedents set by Poe.

Edgar Allan Poe brought about several changes in the literary style of his time period.  Poe, as a writer, poet, editor and a critical writer influenced not only American literature, but he also had an impact on international literature.  He was one of the first writers to develop the genre of both detective fiction and horror.  Stories like “The Pit and the Pendulum,”  “The Black Cat,” “The Tell-Tale Heart,” and “The Fall of the House of Usher,” as well as poems like the “Raven” set him apart from other writes of his time.  “Many anthologies credit him as the "architect" of the modern short story. He was also one of the first critics to focus primarily on the effect of the style and of the structure in a literary work; as such, he has been seen as a forerunner to the "art for art's sake" movement.”  Poe’s style still impacts writers today. "Nearly every important American writer after Poe shows signs of influence, especially when working in the gothic mode or with grotesque humor. The French, Italians, and writers in Spanish and Portuguese in the Americas acknowledge and demonstrate their debts to Poe in technique and vision."  Steven King, Clive Barker and others have followed in the footsteps of Poe.  The genre of horror is bigger today than ever and Edgar Allan Poe was at the forefront of this style of writing.

Poe was the father of the modern-day detective story and also the short story. He also wrote primarily of the macabre and introduced his readers to ambiguity of the characters and places so they would focus on the plot and theme.