Milton's Areopagitica (1644) is one of the most significant texts in the history of the freedom of the press, and yet the pamphlet's clandestine printers have successfully eluded identification for over 375 years. By examining distinctive and damaged type pieces from 100 pamphlets from the 1640s, this article attributes the printing of Milton's Areopagitica to the London printers Matthew Simmons and Thomas Paine, with the possible involvement of Gregory Dexter. It further reveals a sophisticated ideological program of clandestine printing executed collaboratively by Paine and Simmons throughout 1644 and 1645 that includes not only Milton's Areopagitica but also Roger Williams's The Bloudy Tenent of Persecution, William Walwyn's The Compassionate Samaritane, Henry Robinson's Liberty of Conscience, Robinson's John the Baptist, and Milton's Of Education, Tetrachordon, and Colasterion.