She runs like a panicked animal to where she parked the car…She’s driving way over the speed limit, but she doesn't care. She has to get away.
-- Narration (Prolgoue)

Importance: This line describes Karen as she rushes away from the abandoned restaurant at the beginning of the novel. Her panic sets the tone for the entire novel, which is a thriller based around the feeling of personal danger and paranoia.

Tom’s heart is full, looking at his wife…Those are the lips he kisses every morning and every night.
-- Narration (chapter 4)

Importance: This quotation describes Tom's feelings as he visits Karen in the hospital. Tom's feeling of love establishes the tone of their relationship, although that love becomes somewhat disrupted by the turmoil of the story.

It’s as if [Karen] rose, fully formed, at the age of thirty, when she moved to New York State.
-- Narration (chapter 17)

Importance: This quotation is in the context of...