Often times, dreams play the part of premonitions of death.  In Julius Caesar, Calpurnia has a dream three times that Caesar is murdered and so, she begs him to stay home.  He says to her Cowards die many times before their deaths, / The valiant never taste of death but once. (Julius Caesar, II, ii, 32-37). He is also warned by his guards, who have sacrificed a heartless animal and by the man in the street, beware the ides of March, but since it his fate, and it has been dreamt, he is killed, with the famous line, Et tu, Brute? meaning, you too Brutus? In Romeo and Juliet, Romeo has a dream of dying young, but quickly dismisses it when Mercutio tells him his fears are nonsense.  Little do they know, this is a premonition of death, and he will soon kill himself because he thinks Juliet is dead.

            King Richard in Shakespeares Richard III has an epiphany that maybe he should be more grateful for his life when he dreams that he has been injured in battle. Give me another horse! Bind up my wounds! / Have mercy Jesu! Soft, I did but dream. / O coward conscience, how dost thou afflict me? (King Richard III, V, v, 133).  He is shaken by this dream and as a result starts to go a bit crazy, thinking over and over about his love for himself and questioning why he would dream such a thing, blaming his conscience, not suspecting for a moment that this is a premonition of death and perhaps he should live more carefully in the near future.  This is an example of a dream that is not recognized for what it is, and perhaps is intended to only give the audience a foresight to what is coming.  

            Dreams are used to inform in Hamlet. In the very beginning, a ghost or apparition comes to Hamlet in the form of his father and tells him to avenge his fathers murder.    The ghost tells Hamlet who committed the murder in saying that The serpent that did sting thy fathers life / Now wears his crown. (Hamlet, 1.5.38-39), meaning that it was Hamlets uncle who has committed the murder.  The ghost also tells Hamlet that his mother, the Queen, had a hand in the method of the killing.  Without the appearance of this ghost, the audience would not know about the untimely death of King Hamlet or about the scandal his mother has committed by then marrying the late Kings brother, Hamlets Uncle Claudius.  Later in the play, Hamlet is torn amongst the options of what to do.  He feels that if he kills his Uncle while he is praying, Claudius may still go to heaven.  His famous To be or not to be soliloquy ends with his thought that his answer will come to him in his dreams,  To sleep, perchance to dream- ay, there's the rub. (Hamlet III, i, 65-68). 

Often when one is intent on killing, an answer if you will, comes to them in their dreams, foreshadowing their fate, or perhaps the method of the killing.  Caliban seems very intent on killing Prospero, but at the same time, does not do anything rash about it. He shows that he is levelheaded and capable of intellectual thought.  A wise man once pointed out that if Caliban is such a savage, why does he give one of the most beautiful speeches in all of Shakespeare? 

CALIBAN.
Be not afeard: the isle is full of noises,
Sounds, and sweet airs, that give delight, and hurt not.
Sometimes a thousand twangling instruments
Will hum about mine ears; and sometimes voices,
That, if I then had wak'd after long sleep,
Will make me sleep again: and then, in dreaming,
The clouds methought would open and show riches
Ready to drop upon me; that, when I wak'd,
I cried to dream again.
     ~ (Act III, Scene II)

The speech is a wish, a wish that he could keep sleeping and keep dreaming, because in his dreams, the world is perfect and he can simply be, not a slave, but a human being.  The purpose of the speech is to sway the Audience.  It is inspired by his dream, and is meant to invoke pity and compassion for Caliban, even though the original thought is to despise him for what Prospero says Caliban did to Miranda. 

            Often in Shakespeares plays, the characters struggle with the difference between the dream world and the real world.  Prospero, from The Tempest tells Ferdinand and Miranda that We are such stuff / As dreams are made on and our little life / Is rounded with a sleep (The Tempest, IV, i, 156-157).  He is suggesting that perhaps their life is a dream.  This idea fits, since the setting of the play is a magical island, one that does not indulge in being a part of the real world.  This island is inhabited solely by magical creatures and human beings, and even fantastical figments of the imagination.  On the other hand, in A Midsummer Nights Dream, there is a very distinct break between the dream world or fairy world and the world of the mortals, the lovers.  Bottom is the character that brings the two worlds together, as he is the only character who passes between the two, in Oberons effort to humiliate the fairy queen, his love, Titania.

            Through all of these plays and many more, dreams play a key role.  They enlighten, they inform, and they move the plot.  Whenever something cannot be obviously stated, it is dreamt.  Dreams are magical, mystical, and downright puzzling, but We are such stuff / As dreams are made on and our little life / Is rounded with sleep