The primary literary technique that unifies his stories is Poe’s concept that the short story should produce a powerful, single impact, usually involving something bizarre or horrible. Another major technique showing Poe’s great skill is his manipulation of point of view. Half of his stories demonstrate Poe’s concern with a consistent and reliable narrative voice. “The Black Cat” and “The Cask of Amontillado” both feature a first-person narrator who is a major participant or mover; “The Fall of the House of Usher” introduces a first-person narrator who is a major observer; and “The Masque of the Red Death” uses a third-person limited narrator. Each of the stories may be studied for the effects of Poe’s control over point of view. The other half use a delusional, unreliable, and mainly homicidal narrator. Another unifying topic is Poe’s uses of setting and detail, ranging from the particular to the symbolic, from the ordinary to the macabre.