This article is designed to provide information regarding the development of punched card technology for use in both census and commercial applications. After describing the different types of technology and how they were used, this article provides a detailed description of census requirementsand, in particular, the German censuses of 1925, 1933, and 1939-in an effort to counter arguments that German authorities used the results of these censuses during the Holocaust period. Extensive references are provided to enable others to have access to information from that era.