One of the most comprehensive humanities and social science research projects in Canadian history, the Canadian Century Research Infrastructure is a five-year, pan-Canadian initiative to develop a set of interrelated databases centered on census records for the 1911-1951 period. The databases being developed from manuscript census records for the period 1911 to 1951 form the core of a much larger research infrastructure, the objective of which is to construct an evidentiary foundation for research on the transformation of Canadian society from the late 19th century to the later 20th century. To construct this evidentiary foundation, the CCRI will have two major components: primary sources and secondary sources.