The largest portion of the Collection consists of 3 x 5 bibliographic note cards (in Dutch). This is also the only series that includes original manuscript material. A preliminary index has been created to assist the researcher.  Copies of published articles in Dutch and English comprise Boxes 1 and 2. Arrangement is by language, and by publication. The articles written for the Dutch newspaper Trouw (1949-1956), and Opbouw (1957-1972) are foldered chronologically. Journal articles in English are arranged alphabetically, while articles in Dutch are arranged chronologically under the journal title, with no attempt to list individual article titles. Fifty-one audio cassette tapes (ca. half in English, remainder in Dutch) provide voice recordings of Dr. Rookmaaker on the topics of art, culture, music, philosophy, and the Bible. He lectured in the United Kingdom, the United States, and Canada, as well as in his native Netherlands.