“…For two generations of researchers, studies focused either on very small areas (a village or small town, or possibly a rural county) or on very small samples, often based on names that were rare or began with only a few letters of the alphabet. The best-known research, such as studies of social mobility [12], [38], [71], urban social change in Philadelphia [29], [34], the relationship between religion and fertility among the Mormon pioneers in Utah [6], [7], and the demographic history of France [8] and the Belgian city of Antwerp [54], were limited by the effort required.…”