Description of Incident: During the 1920s, the New York Public Library engaged in self censorship where librarians would choose materials to catalogue separately. These books would only be available if patrons asked for them specifically.

Results of Incident: In the 1940s and 1950s, professional librarians created guidelines for all the librarians to follow. These objective guidelines prevented the librarians from making subjective decisions on which materials should be available only by request.