All these themes, dystopian society, censorship, and freedom of the individual, are addressed in the 1967 Vineyard Films' (Universal) version of Fahrenheit 451. Although the film reiterates the themes and basis of the book, there are many differences to contrast.
In examining the film and novel, one important item to note is that the same actress, Julie Christie, plays both Linda (Mildred's name in the film) and Clarisse. When looking at this casting decision, one can deduce that the film director, Frances Truffault, purposefully made this decision to show the audience that the women are similar in the way that they cannot continue as they are in the present society. Although the two women are dramatically different in their beliefs, Montag continually searches for signs of Clarisse's energy and enthusiasm in his wife. Montag, is not focusing upon their physical appearance; he's instead trying to find the internal wisdom and soul of the two women that he sees.
Unfortunately, Clarisse dies in the book when Montag begins to understand her. However, in the film, Clarisse survives and, in fact, becomes his teacher (she, in a way, replaces the character of Faber from the book who doesn't appear in the film). She is the character who guides Montag to the book people hiding in the woods outside the city.
Contemplate the fact that in the book, no women are present at the end of the novel, but in the film, women play a role in the reconstruction of the new society. Possibly, this difference reflects that the book was written in 1953, whereas the film was made 14 years later.
Regardless of the differences between the film and the book upon which the film is based, both stories of Fahrenheit 451 tackle the issues of a society that has allowed its government to take total control. Chillingly, people in this society have forgotten their histories and have allowed themselves to become victims of propaganda and censorship. In following the protagonist, Guy Montag, through his struggle and rebirth, the reader (and viewer) are given the opportunity to see that the human spirit triumphs and that the important knowledge that books can impart will never be destroyed.