After you have read book 1 you need to think about the character Clarisse. Describe Clarisse’s effect on Montag and her function in the novel. How and why does she change him? Why does she vanish from the novel?
Clarisse's name is probably significant; she helps Montag see things more clearly than he had previously seen then. She functions as a kind of muse, and she is obviously the polar opposite of his wife. I always find it remarkable that she seems someone from the late 1960s even though the book was published in the early 1950s.
Clarisse is a free spirit. Until he meets her, it never occurs to Montag to question the status quo. After what happens to her, he starts to think about the books he's burning and decides to try reading them instead of burning them, thus becoming a rebel.
The disappearance of Clarisse serves to show Montag exactly what the stakes are. If he chooses to follow her advice and her example, Montag could disappear too.
Symbolically, she represents most of the virtues that Bradbury presents in the novel relating to free-thinking and living a truly human life with curiosity, with honestly, and without fear. She's an individual in a world where that is a rare thing.
She changes Montag by making him think. He's clearly already leaning in that way (after all, he does steal and hide the books) but she really pushes him hard in that direction. Then she disappears because A) her work is done and B) her death can push him more to understand the true nature of the society he lives in.
Clarisse is a breath of fresh air to Montag. Before, he would just lead his life as others told him to and would never question anything that was told to him. Her character provides a very good reason for him to change his ways, thus turning the actual book into a story. Without her, there would be no story. She dissapears from the novel becuase Montag starts developing on his own and she is no longer needed. She gave him initial push, but now he can think and funciont on his own.