[2] Clandestine publications were plentiful during the Enlightenment era in 18th-century France, circulating as pamphlets or manuscripts,[3] usually containing texts that would have been considered highly blasphemous by the Ancien Régime, sometimes propounding outright atheism.
These clandestine manuscripts particularly flourished in the 1720s, and contained such controversial works as Treatise of the Three Impostors and the Catholic priest Jean Meslier's atheistic Memoirs.
[4] Both texts were later published in edited versions by Voltaire, but handwritten manuscript copies have been found in private libraries all over Europe.
Works that are originally published by clandestine means may eventually become established as canonical literature, such as Das Kapital and El Buscón.
The Olympia Press in Paris published several 20th-century English-language writers, including Henry Miller, who were facing censorship and possible prosecution in their own country at the time.