his work entitledThe Rhetoric of Fiction. But prior to the term being coined, many notable authors used the technique, such as Poe, William Faulkner, Emily Bronte, Anton Chekhov, and more.

An unreliable narrator carries with it certain characteristics. For instance, the narrator's credibility has to be seriously compromised. This may be evident immediately, or it may take more time to discover. A modern example of this type of narration is The Girl on the Train by Paula Hawkins. In that novel, the narrator is unreliable because of her alcoholism and inability to remember events clearly. Readers assume she is at fault for the terrible events of her life only to learn later that her ex-husband is an abusive social deviant.

Montresor is an unreliable narrator because he is a social deviant. He thinks it's fine and even necessary to kill Fortunato because he insulted him. Alternately, consider the idea that Montresor only imagined killing Fortunato and told us a tall tale. He's still an unreliable narrator because we can't trust him.

But an unreliable narrator is more than just a character we can't trust. An unreliable narrator also conceals information from the audience, as in the example of Montresor not telling the audience what Fortunato did to insult him. Montresor tells the tale expecting that the audience will agree with his viewpoint that it was necessary to kill Fortunato and that he was completely justified in doing so.

Consider the opening paragraph:

The thousand injuries of Fortunato I had borne as I best could, but when he ventured upon insult I vowed revenge. You, who so well know the nature of my soul, will not suppose, however, that I gave utterance to a threat. At length I would be avenged; this was a point definitely, settled—but the very definitiveness with which it was resolved precluded the idea of risk. I must not only punish but punish with impunity. A wrong is unredressed when retribution overtakes its redresser. It is equally unredressed when the avenger fails to make himself felt as such to him who has done the wrong.

It must be understood that neither by word nor deed had I given Fortunato cause to doubt my good will. I continued, as was my in to smile in his face, and he did not perceive that my to smile now was at the thought of his immolation.

Montresor supposes a familiarity with the audience with the words "You, who so well know the nature of my soul, will not suppose, however, that I gave utterance to a threat." Well, the audience doesn't know Montresor at all. So it is a type of madness to assume a familiarity with those whom one is not familiar with. He is trying to establish credibility and relationship where there is none. He is trying to rationally justify murder.

In addition to Poe's use of an unreliable narrator, he also uses the Gothic style of writing in this story, as with most of his literary work. Gothic literature deals with elements of fear, death, and horror, all of which are present in "The Cask of Amontillado." The Gothic style also infuses some Romantic elements, such as nature, individuality, and high emotion. There are references to nature in the nitre of the catacombs in Poe's story, and the high emotion includes Fortunato's fear as well as the suspense the audience feels.

The characters's names in "The Cask of Amontillado" are meant to be symbolic or darkly humorous. The name Fortunato means "fortunate" or "lucky," and he is, of course, not so because he is murdered by Montresor. Montresor's name means "my treasure," which could be taken to mean his treasure in the catacombs, the body of his enemy, Fortunato. The men's costumes are ironic, as Montresor is dressed not unlike the grim reaper and Fortunato is dressed like a clown or fool.

There are other instances of symbolism, such as the coat of arms and motto of the Montresor family: Nemo me impune lacessit. The translation is "no one harms me with impunity," and it is ironic that Fortunato would ask Montresor about it, since he has harmed Montresor, and he will be punished for it.

The setting is Carnival, which is the last night of revelry before the period of Lent. Montresor uses it to his advantage because he knows Fortunato will be intoxicated and therefore easy to overpower. Again, it is situationally ironic, because Lent is a period of reflection on and repentance for one's sins.

A major literary device used in "The Cask of Amontillado" is dramatic irony.  At the beginning of the story, Montresor makes it clear to the reader that he plans to get revenge on Fortunato for the "thousand injuries" that he has had to bear from him.  Fortunato, however, is completely unaware of the Montresor's plans because Montresor is behaving in a friendly manner (on top of the fact that Fortunato has had too much to drink at the carnival).  Montresor appeals to Fortunato's ego by telling him that he respects his knowledge of fine wines, which is all just a rouse to get him into the cellar.  As the two walk through the catacombs, the reader is aware that Fortunato is about to meet an ill fate, yet he remains unaware.  So, dramatic irony is at play in the story.

Though his dark subject matter is not universally appealing, Edgar Allan Poe was a superb technician and his skill in crafting this revenge tale through the use of symbolism is undeniable.

A single example among the many uses of symbolism is found in the names of the principal characters, Montresor ( French for "my treasure") and Fortunato (ltalian for "fortunate one").  Montresor is pathologically angry with Fortunato for a series of slights that are described only as "a thousand injuries". Exacting revenge through Fortunato's destruction is what is most precious to Montresor.

Fortunato, symbolically costumed as a fool for Carnival, is merrily oblivious to Montresor's anger and readily follows him underground to sample a rare sherry. When Montresor overpowers and entombs Fortunato, he literally buries his "treasure." Fortunato's name, then, can only be deemed ironic.

 Poe, Edgar Allan.  "The Cask of Amontillado"

http://xroads.virginia.edu/~hyper/poe/cask.html

The Cask of Amontillado is a short story on the topic of revenge that deals with the frightening concept of being buried alive (although in this case it is more of an immurement, or being buried behind a wall). This story, like a couple others by Poe including "The Tell-Tale Heart" is written from the (first person) perspective of the murderer. It is a very dark story and, even at the end, the murderer does not seem to have any remorse.

One of the main aspects of the story is the irony found throughout. Irony is defined as the use of words to convey a meaning that is different from the literal meaning. One example is the name Fortunato (given to a man who meets a very unfortunate end). Another is the fact that the story, dark and disturbing, takes place during the joyful time of Carnival. Google searching the title of the story  (in quotation marks) and the word irony will help you find a number of examples.

Poe explained his style as arabesque, one of horror and torment.  Irony and wit are part of the grotesque playfulness of this arabesque and the pattern has balance and integration of  these elements as psychological tension and horror parallel the action and dialogue.

Much like the winding catacombs that narrow and darken, the workings of the narrator are twisted and darkly sinister. In fact,the narrative is controlled by this vengeful narrator whose obsession with revenge finds grotesque humor in ironic jesting with Fortunato about his being a mason--not the secret society member, but a bricklayer who is about to entomb his victim.  With a perversely feigned concern for his victim's health, the narrator urges Fortunato to turn back:  "...it is very damp.  Once more let me implore you to return."  Then, the narrator adds to the horror: 

No?  Then I must positively leave you.  But I must first render you all the litttle attentions in my power.

This torment of Fortunato increases as Montesor lays down the tiers of bricks which soon entomb the connosieur.  Still Montesor calls to his enemy, then walling him in further, increasing the psychological tension. Finally, the narrative has completed its windings and Fortunato begs his tormentor:  "For the love of God, Montresor."  With grotesque irony and the final arabesque, ornamentation of horror, Montesor responds, "Yes,...for the love of God" and hastens to "an end of my labor."

This story was part of the American Gothic movement, stories that featured the dark side of human nature, and were often set in eerie or creepy places.  The catacombs definitely fit that description, and Montresor's resolutely and calmly planned revenge fit the feature of exploring the darkness that humans are capable of.

It is also written in first-person, which allows the reader to get inside the narrator's head.  This way, we know the sinister thoughts of Montresor, and know he wants revenge.  We just don't know how until the narrator himself reveals it to us.  That first-person angle adds suspense, because the action is revealed as it occurs, from one perspective only.  The narrator's voice and style is also very distinct; Montresor is a calculated, calm, unrepentant murderer, and it shows in his commentary.