A website devoted to listing books that were banned from schools, libraries etc. From censorship quotes:

“You see these dictators on their pedestals, surrounded by the bayonets of their soldiers and the truncheons of their police. Yet in their hearts there is unspoken – unspeakable! – fear. They are afraid of words and thoughts! Words spoken abroad, thoughts stirring at home, all the more powerful because they are forbidden. These terrify them. A little mouse – a little tiny mouse! -of thought appears in the room, and even the mightiest potentates are thrown into panic.”
– Winston Churchill

A book on the list (I love those comments):

Anderson, Janice. The Life and Times of Renoir. Shooting Star Pr. Restricted at the Pulaski, Pa. Elementary School Library (1997) because of nude paintings in the book. Well, duh. It’s Renoir, people.

Bradbury, Ray. Fahrenheit 451. Ballentine. Ironically, students at the Venado Middle School in Irvine, Calif. received copies of the book with scores of words–mostly “hells” and “damns”–blacked out. The novel is about book burning and censorship. Thankfully, after receiving complaints from parents and being contacted by reporters, school officials said the censored copies would no longer be used (1992).