Arguably one of the most important works on the philosophy of anti-censorship. The text is a tough read for a modern audience, but you can read it here.

A quotation from Areopagitica is prominently displayed over the entrance to the renovated Main Reading Room of the New York Public Library: "A good Booke is the precious life-blood of a master spirit, imbalm'd and treasur'd up on purpose to a life beyond life".

The Supreme Court of the United States has referred to Areopagitica, in interpreting the First Amendment to the United States Constitution, to explain the Amendment's protections. The Court has cited Areopagitica by name in four cases. Most notably, the Court cited Areopagitica in the landmark case New York Times Co. v. Sullivan to explain the inherent value of false statements. The Court cited Milton to explain the dangers of prior restraint in Times Film Corp. v. City of Chicago et al. Later, Justice Douglas concurred in Eisenstadt, Sheriff v. Baird, citing the pamphlet to support striking down restrictions on lecturing about birth control. Finally, Justice Black cited Areopagitica when he dissented from the Court's upholding of restrictions on the Communist Party of the United States against a free speech and free association challenge in Communist Party of the United States v. Subversive Activities Control Board. In each instance, Milton is cited by the Court's members to support a broad and expansive protection of free speech and association.