In the context of the Community Programme of Population and Housing Censuses 2001, Statistics Netherlands compiled data for the National Census 2001. The census was in fact a virtual census, exclusively using statistical information already available, like databases, registers and surveys. In the first part of a comprehensive explanation, information is given about sources, methods and definitions. Some general observations are made regarding the results presented in this publication and the symbols used. Various tables require a more detailed explanation. The second part of the explanation elaborates on adaptations made in the table layouts. The National Census 2001 includes 40 detailed Excel tables. Tables 1-28 provide statistical information on the national level, tables 29-37 provide statistical information on the regional level and tables 38-40 refer to municipalities. There are 8 tables dealing with housing (tables14, 24-29, 37 and 39), 2 tables dealing with commuter traffic (tables 20 and 40) and 30 tables on demographic particulars. Demographic subjects are subdivided into various categories, i.e. economic activity, profession, education level, branch of industry, etc..