Just found this site on forbidden books, with a number of great quotes. My particular favourite is the following by Churchill – simply because it has been one of my own observations and pet peeves for many years.
"Everyone is in favor of free speech. Hardly a day passes without its being extolled, but some people's idea of it is that they are free to say what they like, but if anyone else says anything back, that is an outrage."
-- Winston Churchill
Frankly, the list is a little tame and seems to focus on books banned by local busy-bodies in the United States. There are a number of books out there that are really banned, and for which one can go to prison if caught distributing or even just owning them.
Granted, the works of the Nazis and the Holocaust deniers are intellectually offensive, but that’s no reason to ban them. The difference between prohibiting books that deny the reality of Holocaust and prohibiting books that deny the divine nature of the Koran is, after all, not a matter of principle but of taste.
It is hard to credibly accuse the Iranian Mullahs and Chinese Communists of censorship when they go after the authors novels and cute self-help pamphlets, while Western democracies jail the authors of pseudo-historical tracts.
Luke 6:42 is and remains a good general principle.