At the start of Fahrenheit 451 Guy Montag is content in his job as a fireman. He and the other firemen respond to reports of people who have books and then race to their homes and burn the books. Once Montag meets his new neighbor, Clarisse McClellan, he begins to question his life, his career, and his society. On the job he finds himself stealing one book after another as he becomes increasingly fascinated by the power of the forbidden printed word. Fahrenheit 451 is built around Montag's awakening: his choice to steal and read books and think for himself. This choice leads to the disruption of his career and marriage. It also sparks his decision to join a rebel group of book lovers and shape an alternative to the existing society with them.
Captain of Montag's firehouse, Beatty is one of the book's most ominous and complex characters. Extremely perceptive, he senses from the beginning that Montag is hiding his theft of and fascination with books. Yet Beatty plays a sadistic game with Montag, never accusing him directly but repeatedly implying he knows what Montag is doing. Beatty himself has a paradoxical relationship to books. He has read widely in an age when books are illegal, yet as a fireman he destroys books as a social threat. He is always ready with apt literary quotations, but he uses them to argue that reading is dangerous to society and that therefore books deserve to be destroyed.
Clarisse McClellan is only 17 years old when she and her family move next door to Montag. However, she is the catalyst who changes Montag's life, inspiring him to question the society in which they live. She also opens the door to his inner life. She inquires about his thoughts and feelings, going against the grain of a culture that frowns on self-awareness in favor of vapid self-centerdness: "Clarisse's favorite subject wasn't herself. It was everyone else." Montag looks forward to seeing Clarisse more than anyone else, even though their conversations often disturb him. Then one day she simply disappears. A few days later his wife, Mildred, casually mentions that Clarisse has been hit by a car and killed. But after Clarisse's death her powerful effect on Montag never wanes. He remembers her often and vividly. She becomes the standard by which he judges society and sees how deeply it lacks humanity.
If Beatty is his society's enforcer, Mildred is the end product of the society. She does not reflect as Beatty or Montag do on the meaning of the society, how it works, or why. She isn't stupid, but she prefers an unexamined existence. Mildred also lacks self-awareness or a deeper connection to others. After she overdoses and nearly kills herself, she remembers nothing about it. Dominated by entertainment technology, Mildred lives for the programs televised on the multimedia screens filling her home and is rarely without a Seashell Radio stuck in her ear. Mildred and Montag have a pathetic marriage, even a tragic one. It is not clear whether they have ever loved one another. Despite this situation, when Montag decides he wants to risk social rejection and death by reading books, Mildred supports him for a time, trying halfheartedly to read them as well. Eventually, though, social pressure is too much for her, and she alerts the authorities about her husband's books and then leaves the marriage.
A year before he met Clarisse, Montag met Professor Faber in a park. A retired English professor, Faber loves books and understands why they are so important. As Montag becomes more deeply drawn to books, he turns to Faber for guidance. Faber becomes a mentor to Montag, explaining the importance of culture and thought. He also gives Montag a tiny radio Montag hides in his ear, through which Faber counsels Montag. Most importantly Faber points him toward the rebel group of book lovers Montag eventually joins. It is important to Montag that Faber cares about what is happening to him and is there for him, and he is willing to protect Faber in return. When Beatty discovers the tiny radio and threatens to uncover Faber, Montag kills Beatty.
Granger appears only in Part 3 of the novel. He takes over as Montag's guide once Montag leaves Faber (and his former life) behind. When he was an active professor, Granger wrote a book on the relationship of the individual to society. Now he is the leader of the group of people who memorize books. He helps Montag escape the Mechanical Hound, and he narrates and explains the fake hunt for the false Montag. Granger serves as a mentor to Montag. Granger explains to him how to survive on the fringes of society. He also provides Montag with an alternative philosophy of how to live when he shares personal stories about his grandfather, an active free-spirited sculptor.