Poe is internationally recognized as a master of suspense. This article analyzes suspense in a way that is helpful to understand the mechanics used by the author. So often we don't take the time to think about how things are done, though of course it is fun just to be entertained.
Suspense is one of those devices that can be easily messed up if it is done wrong, as we have all seen in so many low budget "B" movies or in second rate dime novels. Poe, on the other hand did it very well and inspired many other great masters like Hitchcock.