Summary from wikipedia.
"The Raven" is a narrative poem by American writer Edgar Allan Poe, first published in January 1845. It is often noted for its musicality, stylized language, and supernatural atmosphere. It tells of a talking raven's mysterious visit to a distraught lover, tracing the man's slow descent into madness. The lover, often identified as being a student,[1][2] is lamenting the loss of his love, Lenore. Sitting on a bust of Pallas, the raven seems to further instigate his distress with its constant repetition of the word "Nevermore". The poem makes use of a number of folk and classical references.
I love this poem and is one that I read over and over as it colours the slow transition towards madness very well. The pacing is beautiful. Everything about is wonderful. Nothing will ever come close to how wonderfully dark it is. Nevermore.