They rebel by reading books and memorizing the books. Montag stole books from the houses he helped to burn as a fireman. He was curious about what would make people willingly break the law, so he stole a few books. Clarisse asked Montag early in the story, "Are you happy?" When Montag realized that the answer to the question was "no", he decided to investigate the books and he began reading. As he read, he realized that the problems in society weren't because the books, the problems were due to society's lack of awareness brought on by lack of reading. He rebelled by killing Captain Beatty and running away to join the Book People. Granger rebelled by leading the Book People - a group of rebels who memorized, then burned, books. Each person became a book, reciting it for anyone who wanted to "read" the book. By not possessing the books, the people were in less danger of being caught and punished.
Montag, Clarisse, and Granger rebel against the authorities in Fahrenheit 451 by violating the rules of the society in which they must live.
Montag, a fireman, has pilfered books when he is sent to burn them, and he has hidden them "behind the grill" of the ventilator. He has also talked with a man named Faber, a college professor whom he has met in a park.
Later, Montag takes more books and reads aloud in front of his wife Mildred and her friend, but a frightened Mildred turns him in to the authorities. When Montag realizes that Beatty has found him out, he sets Beatty on fire. He then contacts Faber and flees, following Faber's directions in order to escape the Mechanical Hound.
Clarisse reads, walks at night, stargazes, and "[T]hinks crazy thoughts." Furthermore, she smells flowers and truly examines things when she looks at them. During her brief encounter with Montag, she tells him
"I like to smell things and look at things, and sometimes stay up all night walking and watch the sun rise." (Part I)
Above all, Clarisse refuses to be afraid and restricted by the mindless activities of the society, such as driving so fast that things are a blur, watching the "parlor walls," or going to the races and Fun Parks.
Granger, another former professor who finds the existing state of society repellent, has authored a book that analyzes the relationship between the individual and society. Because of his rebellion against the status quo, Granger has gone into hiding and formed a society that he calls "the odd minority crying in the wilderness." He describes the members of his group to Montag as "nothing more than jackets for books."
Granger welcomes Montag to his group of outcasts who sustain the life of books by means of their having memorized them word for word. He tells Montag that when the war is over and the day comes that books can again be written and published, the people will be summoned so that the written word can again be set in type and preserved for others, or at least until "we might have to do...the whole thing over again."