Areopagitica is a book written by English poet John Milton in 1644. He wrote it to protest against censorship. Its full title is "Areopagitica: A speech of Mr. John Milton for the liberty of unlicensed printing to the Parliament of England". Today, his book is called a tract. In the tract, Milton tries to defend the freedom of expression. Today, many people see it as one of the best defenses of the freedom of press ever written.