History has taught you nothing if you think you can kill ideas. Tyrants have tried to do that often before, and the ideas have risen up in their might and destroyed them.

You can burn my books and the books of the best minds in Europe, but the ideas in them have seeped through a million channels and will continue to quicken other minds.

—  May 9, 1933: Helen Keller’s scorching letter to the Nazis about book-burning, censorship, and the inextinguishable freedom of ideas.