In the first half of the twentieth century, censorship was mainly an issue for the Protestant and Catholic Churches. The ways in which both churches applied censorship differed, however, as much as their views on the Christian faith. Abraham Kuyper, the founding father of the Dutch Reformed Church, advocated a form of internal censorship, led by a 'pure Christian spirit'. This placed the responsibility for censorship in the hands of schools and the family. Instead of banning the reading of certain books, they gave positive or negative recommendations in order to enhance moral awareness.
Although canonical censorship by the Protestant Church had disappeared by the early nineteenth century, a century later the Catholic population were still being kept on the straight and narrow by means of the Book Act which was part of canon law. This Roman Catholic law on reading was part of the Corpus Iuris Canonici (CIC), which was in force from 19 May 1918 until 25 January 1983 and banned certain categories. For specific titles, one turned to the Index Librorum Prohibitorum (List of prohibited books). Besides these provisions, the bishops were also authorised to ban the reading of certain books. The Book Act often caused practical problems. For many Catholic booksellers, publishers and libraries it was not always clear as to which books were and were not banned. In order to solve this inconvenience, the Informatie Dienst Inzake Lectuur (Information Service Regarding Reading Matter, IDIL) was established on 1 August 1937. It was based on the Book Act and gave reading recommendations which were generally taken to be regulations. The liberalisation in the 1960s transformed the IDIL into a neutral organisation informing the public about newly published books. In 1970 the Catholic information service was discontinued and two years later the service to libraries was taken over by the Nederlands Bibliotheek en Lectuur Centrum (Netherlands Library and Reading Centre, NBLC).
The most totalitarian and effective form of censorship took place during the German occupation. From 1940 to 1945, book censorship driven by the national-socialist ideology was in place, using the effective means of paper allocation. In order to publish, publishers were made dependent on the regulations and decisions of the paper allocation authorities. This was in the first place the Afdeeling Boekwezen van het Departement van Volksvoorlichting en Kunsten (Book Business Division of the Department of Public Information and Arts, DVK). A second authority which approved publications was the Referat Schrifttum of the Reichskommissariat. In a few cases organisations such as the National-Socialist Movement (NSB) or the Dutch SS also tried to ban books. The Sicherheitsdienst (SD) was closely involved in the monitoring of banned books as well. In order to facilitate this, all printed matter was given a K number, through which the responsible printer could be traced. From January 1942 onwards, the reading regulations of the Nederlandsche Kultuurkamer (NKK) came into force, which prescribed that all those who had a part in the production of books (writers, translators, printers, publishers and booksellers) were required to register.
Besides the religious divisions and the book censorship based on the national-socialist ideology, now and again the Dutch authorities also imposed censorship on certain books on moral grounds. Usually these were books which were considered 'offensive' or hurtful to certain people or groups.
