This copy is the first Latin edition of the famous Letttres Provinciales by Blaise Pacal. The book has been translated including the additions on pp. 510-608 by Pierre Nicole under the pseudonym Wilhelm Wendrock, a few months after the original French edition and just as that edition forbidden by the Councl d'État on september 23, 1660 and burnt. The book was printed by Jean Elzevier (...) who had very good relations with the jansenists and were about to publish the first collective edition of the Lettres Provinciales. Pascal came under jansenist influence in 1646. In 1654 Pascal underwent a mystical experience which effected his definite conversion to a religious and jansenist life. In 1655 he took up his residence in Port Royal. Attack by the Jesuits on the Jansenists and on Anotine Arnauld led to the publication in 1656-1657 of eighteen Lettres Provinciales. They deal with two subjects of divine grace and the ethical code of the Jesuits (...) The Lettres written by polite irony and the utmost simplicity, lucidity, and objectivity, were an enormous succes (....)The work was placed on the index and was ordered by the RoyalCouncil to be burnt (1660) (..). (...) He forced the faithful Christian to scrutinize his own conscience, laying bare the depths of desire and the libido which testifiest the persistence of the original sin (...)