Which of his own pieces of writing does poe use to explain his philosophy of composition?

Edgar Allen Poe used his poem, "The Raven," as an example to explain his philosophy of composition. 

Poe's essay, "The Philosophy of Composition," was published in the April, 1846 , issue of Graham's American Monthly Magazine of Literature and Art.  Some other writers have wondered whether Poe indeed followed the rather rigid and methodical method he described in the essay when he was composing "The Raven" or other works of his. 

Nevertheless, it remains an interesting glimpse into how Poe thought about the craft of writing.  He urged striving for brevity and beauty, and have a subject matter that can be appreciated by a universal audience.