.......ONCE u PON a MID night DREAR y, WHILE i POND ered WEAK and WEAR y 

In this line, the capitalized letters represent the stressed syllables and the lower-cased letters, the unstressed ones. Notice that the line has sixteen syllables in all. Notice, too, that the line has internal rhyme (dreary and weary) and alliteration (while, weak, weary). 
Who Is Lenore? It is possible that Lenore, the idealized deceased woman in the poem, represents Poe’s beloved wife, Virginia, who was in poor health when Poe wrote "The Raven." She died two years after the publication of the poem, when she was only in her mid-twenties.  
Criticism Some reviewers in Poe’s day, including poet Walt Whitman, criticized “The Raven” for its sing-song, highly emotional quality. The poem is still criticized today–and often parodied–for the same reason. However, the consensus of critics and ordinary readers appears to be that the poem is a meticulously crafted work of genius and fully deserves its standing as one of the most popular poems in American literature. It is indeed a great work. 
Summary It is midnight on a cold evening in December in the 1840s. In a dark and shadowy bedroom, wood burns in the fireplace as a man laments the death of Lenore, a woman he deeply loved. To occupy his mind, he reads a book of ancient stories. But a tapping noise disturbs him. When he opens the door to the bedroom, he sees nothing–only darkness. When the tapping persists, he opens the shutter of the window and discovers a raven, which flies into the room and lands above the door on a bust of Athena (Pallas in the poem), the goddess of wisdom and war in Greek mythology. It says “Nevermore” to all his thoughts and longings. The raven, a symbol of death, tells the man he will never again ("nevermore") see his beloved, never again hold her–even in heaven.  
 

Once upon a midnight dreary, while I pondered, weak and weary,............[meditated, studied] 
Over many a quaint and curious volume of forgotten lore,....................[archaic, old] [book of knowledge or myths] 
While I nodded, nearly napping, suddenly there came a tapping,...............[example of alliteration] 
As of some one gently rapping, rapping at my chamber door....................[bedroom or study] 
"'Tis some visitor," I muttered, "tapping at my chamber door-  
Only this, and nothing more."................................................................... 

Ah, distinctly I remember it was in the bleak December,.......................[internal rhyme] 
And each separate dying ember wrought its ghost upon the floor...........[glowing wood fragment in fireplace] [formed ash] 
Eagerly I wished the morrow; vainly I had sought to borrow.....................[next day] 
From my books surcease of sorrow—sorrow for the lost Lenore-..............[an end, a pause, a delay] 
For the rare and radiant maiden whom the angels name Lenore-  
Nameless here for evermore.  

And the silken sad uncertain rustling of each purple curtain.......................[example of alliteration] 
Thrilled me—filled me with fantastic terrors never felt before;....................[unreal, imaginary; weird, strange] 
So that now, to still the beating of my heart, I stood repeating,  
"'Tis some visitor entreating entrance at my chamber door-..... ...............[begging, pleading for] 
Some late visitor entreating entrance at my chamber door;-  
This it is, and nothing more."  

Presently my soul grew stronger; hesitating then no longer,  
"Sir," said I, "or Madam, truly your forgiveness I implore;.........................[beg, ask for] 
But the fact is I was napping, and so gently you came rapping,  
And so faintly you came tapping, tapping at my chamber door,  
That I scarce was sure I heard you"- here I opened wide the door;-  
Darkness there, and nothing more.  

Deep into that darkness peering, long I stood there wondering, fearing,  
Doubting, dreaming dreams no mortals ever dared to dream before;  
But the silence was unbroken, and the stillness gave no token,  
And the only word there spoken was the whispered word, "Lenore!"  
This I whispered, and an echo murmured back the word, "Lenore!"-  
Merely this, and nothing more................................................................[Lines 2, 4, 5, and 6 of each stanza rhyme, as here] 

Back into the chamber turning, all my soul within me burning,  
Soon again I heard a tapping somewhat louder than before.  
"Surely," said I, "surely that is something at my window lattice:.................[shutter] 
Let me see, then, what thereat is, and this mystery explore-.....................[there, at that place] 
Let my heart be still a moment and this mystery explore;-  
'Tis the wind and nothing more."  

Open here I flung the shutter, when, with many a flirt and flutter,.................[jerk] 
In there stepped a stately raven of the saintly days of yore;........................[majestic][the distant past] 
Not the least obeisance made he; not a minute stopped or stayed he;........[bow, gesture of respect] 
But, with mien of lord or lady, perched above my chamber door-..................[manner] 
Perched upon a bust of Pallas just above my chamber door- ......................[small sculpture showing the head, shoulders, and chest 
Perched, and sat, and nothing more...........................................................of a person][Athena, Greek goddess of wisdom] 

Then this ebony bird beguiling my sad fancy into smiling, ........................[black][charming, coaxing] 
By the grave and stern decorum of the countenance it wore. ..................[look on its face] 
"Though thy crest be shorn and shaven, thou," I said, "art sure no craven,..[tuft of feathers on head][cut] [coward] 
Ghastly grim and ancient raven wandering from the Nightly shore-.....[See Note 1 below the end of the poem.]  
Tell me what thy lordly name is on the Night's Plutonian shore!"  
Quoth the Raven, "Nevermore.".................................................................[Said, spoke] 

Much I marvelled this ungainly fowl to hear discourse so plainly,........[The narrator is surprised that the raven can speak.] 
Though its answer little meaning- little relevancy bore;.............................[The raven's answer made little sense.] 
For we cannot help agreeing that no living human being  
Ever yet was blest with seeing bird above his chamber door-  
Bird or beast upon the sculptured bust above his chamber door,  
With such name as "Nevermore."..........................................................[See Note 2 below the end of the poem.] 

But the raven, sitting lonely on the placid bust, spoke only .........................[peaceful] 
That one word, as if his soul in that one word he did outpour.  
Nothing further then he uttered- not a feather then he fluttered-  
Till I scarcely more than muttered, "other friends have flown before-  
On the morrow he will leave me, as my hopes have flown before."  
Then the bird said, "Nevermore."  

Startled at the stillness broken by reply so aptly spoken,  
"Doubtless," said I, "what it utters is its only stock and store, ....................[the only words it can speak] 
Caught from some unhappy master whom unmerciful Disaster ....................[learned] 
Followed fast and followed faster till his songs one burden bore-  
Till the dirges of his Hope that melancholy burden bore ...............................[funeral hymns] 
Of 'Never- nevermore'."  

But the Raven still beguiling all my fancy into smiling,  
Straight I wheeled a cushioned seat in front of bird, and bust and door;  
Then upon the velvet sinking, I betook myself to linking  
Fancy unto fancy, thinking what this ominous bird of yore- .........................[sinister, threatening] 
What this grim, ungainly, ghastly, gaunt and ominous bird of yore ...........[the bird is now the image of death] 
Meant in croaking "Nevermore."  

This I sat engaged in guessing, but no syllable expressing  
To the fowl whose fiery eyes now burned into my bosom's core; ................[metaphor comparing the gaze to a fire] 
This and more I sat divining, with my head at ease reclining .......................[trying to figure out] 
On the cushion's velvet lining that the lamplight gloated o'er, .....................[personification] 
But whose velvet violet lining with the lamplight gloating o'er,  
She shall press, ah, nevermore!.............................................................[She will never again press her head to the cushion.] 

Then methought the air grew denser, perfumed from an unseen censer..........[vessel in which incense is burned] 
Swung by Seraphim whose footfalls tinkled on the tufted floor.........................[Angels of the highest rank] 
"Wretch," I cried, "thy God hath lent thee- by these angels he hath sent thee [the narrator is referring to himself] 
Respite- respite and nepenthe, from thy memories of Lenore!.......................[Rest, pause][Drug causing forgetfulness] 
Quaff, oh quaff this kind nepenthe and forget this lost Lenore!".......................[Drink] 
Quoth the Raven, "Nevermore."  

"Prophet!" said I, "thing of evil!- prophet still, if bird or devil!...........................[Poetic license: evil and devil don't rhyme] 
Whether Tempter sent, or whether tempest tossed thee here ashore,  
Desolate yet all undaunted, on this desert land enchanted-  
On this home by horror haunted- tell me truly, I implore-  
Is there- is there balm in Gilead?- tell me- tell me, I implore!".......................[Is there any cure for my deep depression? 
Quoth the Raven, "Nevermore."......................................................................See the Bible, Jeremiah 8:22] 

"Prophet!" said I, "thing of evil- prophet still, if bird or devil!  
By that Heaven that bends above us- by that God we both adore-  
Tell this soul with sorrow laden if, within the distant Aidenn,...........................[Paradise, heaven, Eden] 
It shall clasp a sainted maiden whom the angels name Lenore-  
Clasp a rare and radiant maiden whom the angels name Lenore."  
Quoth the Raven, "Nevermore."  

"Be that word our sign in parting, bird or fiend," I shrieked, upstarting-  
"Get thee back into the tempest and the Night's Plutonian shore!  
Leave no black plume as a token of that lie thy soul hath spoken!  
Leave my loneliness unbroken!- quit the bust above my door!  
Take thy beak from out my heart, and take thy form from off my door!"  
Quoth the Raven, "Nevermore."  

And the Raven, never flitting, still is sitting, still is sitting  
On the pallid bust of Pallas just above my chamber door;  
And his eyes have all the seeming of a demon's that is dreaming,  
And the lamplight o'er him streaming throws his shadow on the floor;  
And my soul from out that shadow that lies floating on the floor  
Shall be lifted- nevermore!........................................................................[The narrator will never again see Lenore.] 
. 

Note 1 The narrator believes the raven is from the shore of the River Styx in the Underworld, the abode of the dead in Greek mythology. “Plutonian” is a reference to Pluto, the god of the Underworld. 
Note 2 The narrator at first thinks the raven's name is "Nevermore." However, he later finds out that "Nevermore" means that he will never again see the woman he loved.