In William Shakespeare's tragedy, Macbeth, darkness plays a vital role in the development of the plot. Darkness itself is associated with many things in modern days such as sleep, dreams, and evil creatures that stalk the night. Also, in the play, darkness is used as a cover for evil deeds that the characters perform (i.e. the murders of Duncan and Banquo).
             Sleep, or the lack of sleep, performs a crucial function. During the first scene of the play a witch says, "Sleep shall neither nigh or day hang upon his penthouse lid" (I, iii, 19-20). Here, sleep is used to foreshadow, for even though the witch is speaking of punishing a sailor for his wife's mistake it carries the theme of punishing the husband for the wife's mistake, which is what happens to Macbeth. In the next act, Banquo, while speaking to his son, Fleance, speaks of sleep. "A heavy summons lies like lead upon me and yet I would not sleep" (II, i, 6-7). Sleep also foreshadows here because as Banquo speaks Lady Macbeth is carrying out the first part of the plot to murder Duncan in his sleep. Immediately after Macbeth stabs Duncan in his bed, he speaks feverishly to Lady Macbeth and in this conversation he says, "'Sleep no more!' to all the house: 'Glamis hath murdered sleep, and therefore Cawdor shall sleep no more: Macbeth shall sleep no more'" (II, ii, 40-42). In this talk sleep, or rather the lack of, represents the madness that will engulf Macbeth later in the play as a result of his transgressions.
             Dreams, also, play quite a large role in the development of the plot. Two quotes, spoken by Macbeth, both represent one, important thing. "Come, let me clutch thee. I have thee not and yet I see thee still" (II, i, 34-35), and "Avaunt! and quit my sight!" (III, iv, 93). These visions, rather "waking dreams," signify Macbeth's descent into madness, which resu...