Censorship in Modern Times

Since 1982, the American Library Association has sponsored Banned Books Week to pay tribute to free speech and open libraries. The tradition began as a nod to how far society has come since 1557, when Pope Paul IV first established The Index of Prohibited Books to protect Catholics from controversial ideas. Four-hundred and nine years later, Pope Paul VI would abolish it, although attempts at censorship still remain. Here, TIME presents some of the most challenged books of all time.