She sees the big picture and the risks involved with getting what she wants. She understands those risks and accepts them as mere obstacles. In this light, she is cold and calculating. She is afraid of nothing and is quick to pray for what it takes: Come, you spirits

That tend on mortal thoughts, unsex me here

And fill me from the crown to the toe top-full

Of direst cruelty. (I.v.38 -- 41)

She knows she lives in a man's world but that does not deter her in the least. She will simply use her husband to get what she wants and she has no doubt that she can do this. She knows he needs her support, however. Later, she tells him, "But screw your courage to the sticking-place / And we'll not fail" (I.vii.64-5). Her support is crucial because it allows him to see them operating as the couple even though he will be the one that draws blood.

While we often see the Macbeth couple operating as one this early scene provides with a glimpse into their individual characters. Macbeth has the desire to be...

Lady Macbeth realizes this about her husband and she knows this could actually led to his downfall. It is important for Shakespeare to establish Lady Macbeth has a strong character in the beginning of the play because Macbeth could never kill on his volition. She is no ordinary woman with ordinary desires. She wants to be queen and she sees a way to make that happen. While the two share this common goal, she proves that she will stop at nothing to reach it. Macbeth needs her voice of support in the beginning of the play to commit the first murder. Macbeth's letter reveals the kind of man Lady Macbeth married and the kind of man she knew she would have to change. Her response to his letter reveals the kind of woman it takes to drive her husband to murder. It is a love letter and it is a letter that reveals absolutes; it reveals her absolute need for power and his absolute inability to stop her.
Work Cited

Shakespeare, William. Macbeth. The Complete Works. New York: Barnes and Noble Books.