The National Organization for Decent Literature was an American pressure group active in campaigning for the censorship of literature. It was largely led by Roman Catholic priests. It was founded in 1938, and ran until the late 1960s. It is famous for banning Madame Bovary in 1954. It campaigned against comic books and what its leaders saw as indecent literature in general.
References
National Organization for Decent Literature Wikipedia(Text) CC BY-SA