Let’s get one thing straight right out of the gate: John Milton’s Areopagitica, published on November 23, 1644, is the single most important prose defense of free speech ever written in the English language. Full stop. Nothing else comes close. Not Locke’s Letter Concerning Toleration, not Mill’s On Liberty, not even Holmes’ Abrams dissent. Those are all brilliant, but they’re footnotes to Milton. Areopagitica is the headwaters.