Four defences of free speech that everyone should read

Every generation, and individual, has to rediscover the arguments for free speech for themselves. Some people learn from major incidents. Some when the censors come for someone close to them, or an opinion that they hold. Others come to believe in free speech because they realise that while being offended on occasion might be terrible, it is nowhere near as terrible as any system designed to make being offended impossible. Fortunately there are short-cuts to finding the best defences of free speech. The English language provides an especially rich tradition on which to draw. From many centuries of literature allow me to list just four works: two classic, two modern.