Bradbury wrote Fahrenheit 451 as a response to an onslaught on books in the 1950s.
Bradbury saw censorship run amok in the 1950s print media. He saw to his horror books being condensed in Readers Digest. Full-length novels were reduced to mince meat, all for the sake of quick and easy.
He also saw TV entertainment and sports threatening the shelf life of books. He feared that a generation of students would be raised without books as a foundation for their education.
As a successful author, he received pressure from political, religious, and other minority groups all wanting to take out or add to his books and stories. He received mail that suggested he add more black characters, get rid of politically incorrect plot-lines, add more women characters, focus more on family values, get rid of all the violence. The list went on and on until Bradbury had had enough.
In "Coda," his author's afterword, Bradbury says:
There is more than one way to burn a book. And the world is full people running about with lit matches. Every minority, be it Baptist / Unitarian, Irish / Italian / Octogenarian / Zen Buddhist, Zionist / Seventh-day Adventist, Women's Lib / Republican, Mattachine / FourSquareGospel feels it has the will, the right, the duty to douse kerosene, light the fuse.