You don't need to put them on the shelf to continue.
There's a note on the wall near the door that reads:
"In here is a tragedy--- art thou player or audience? Be as it may, the end doth remain: all go on only toward death.
The first word at thy left hand: a false lunacy, a madly dancing man. Hearing unhearable words, drawn to a beloved's grave---and there, mayhap, true madness at last.
As did this one playing at death, find true death at last. Killing a nameless lover, she pierced a heart rent by sorrow.
Doth lie invite truth? Doth verity but wear the mask of falsehood? Ah, thou pitiful, thou miserable ones.
Still amidst lies, though the end cometh not, wherefore yearn for death? Will thou attend thy beloved? Truths and lies, life and death: a game of turning white to black and black to white.
Is not a silence brimming with love more precious than flattery? A peaceful slumber preferred to a throne besmirched with blood?
One vengeful man spilled blood for two; Two youths shed tears for three; Three witches disappeared thusly; And only the four keys remain.
Ah but verily... In here lies a tragedy. Art thou player or audience? there is something which cannot become a puppet of fate or an onlooker, peering into a cage."
Now this isn't as hard as it seems, let's analyze the writings part by part.(You'll need to have an idea of what happened in these 5 plays first):
"In here is a tragedy--- art thou player or audience? {Talks about the 5 plays Be as it may, the end doth remain: in general, they all die. all go on only toward death." This is merely an intro}.
"The first word at thy left hand: {This clearly refers to a false lunacy, a madly dancing man. Hamlet. Madness, unhearable Hearing unhearable words, drawn words (his father explaining to a beloved's grave---and there, his death).} mayhap, true madness at last."
"As did this one playing at death, find true death at last. {Talks about Juliet, when Killing a nameless lover, she she kills herself} pierced a heart rent by sorrow." {Macbeth, the deception "Doth lie invite truth? of getting the throne, and Doth verity but wear the mask of falsehood? then the lies and anguish Ah, thou pitiful, thou miserable ones." afterwards.
"Still amidst lies, though the end cometh not, wherefore yearn for death? {Describing Othello, but Will thou attend thy beloved? Truths most obvious, the game and lies, life and death: of turning white to a game of turning white to black and black refers to the black to white." board game Othello}
"Is not a silence brimming with love more {In King Lear, Cordelia precious than flattery? is silent but truly A peaceful slumber preferred to a throne loves her father. Unlike besmirched with blood?" the other two daughters who flatter the king and then fight over the throne with much bloodshed.}
Okay, here we got a certain order for the 5 books, it's like this:
Hamlet - Romeo and Juliet - Macbeth - Othello - King Lear
Which in numbers are: 4 - 1 - 3 - 5 - 2
But there's still some lines missed:
"One vengeful man spilled blood for two; Two youths shed tears for three; Three witches disappeared thusly; And only the four keys remain."
[One vengeful man spilled blood for two]
The vengeful man is Hamlet, when he wanted revenge for his dead father.
He spilled blood for two, meaning his number got multiplied by two:
4 x 2 - 1 - 3 - 5 - 2
8 - 1 - 3 - 5 - 2
[Two youths shed tears for three]
The two youths are Romeo and Juliet.
They shed tears for three, meaning their number got multiplied by three:
8 - 1 x 3 - 3 - 5 - 2
8 - 3 - 3 - 5 - 2
[Three witches disappeared thusly]
The three witches are from Macbeth, they are the witches that told him his future. They disappear, so let's take Macbeth's number out:
8 - 3 - 3 - 5 - 2
8 - 3 - >3< - 5 - 2
8 - 3 - 5 - 2
[And only the four keys remain.]
The four number that remain are the code for the keypad on door, enter the combination 8 - 3 - 5 - 2 to unlock, continue through. Phew.
Oh, and the final few lines:
"Ah but verily... In here lies a tragedy. Art thou player or audience? there is something which cannot become a puppet of fate or an onlooker, peering into a cage."
Have no use, it's a finish. The intro and finishes of most similar puzzles have no significance.
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