In the statistical jungle of the twentieth century, the collection of vast amounts of demographic data is an activity as relentless as breathing. We seldom question our impulse to count ourselves, and to ensure that our births, marriages, deaths, and innumerable other events are duly and permanently recorded. For reasons of both practicality and curiosity, historians and demographers have long attempted to possess the same sorts of data for as much of the past as possible, and have devised ever more ingenious ways of obtaining them. Most recently, such efforts have involved systematic analysis of very large numbers of quantitative records, and have borne fruit in studies of family characteristics, population trends, migration, mobility, and the like. As a result, it is now reasonable to discuss age-specific fertility in seventeenth-century Colyton as well as in twentieth-century London. With understandable pride, the practitioners of the new historical demography have described their accomplishment as one of pushing back the boundary which divides our modern, numerical age from a “pre-statistical past”.