Historical demography is indeed what Father Mols calls it, a “science des confines” (Vol. I, Introduction, p. xvi), a discipline which is doomed to cultivate the boulder-strewn and not easily accessible borderlands between half a dozen fields of learning. In a territory such as this the first clearings are of necessity a matter of small-scale enterprise; that is to say, local research predominates. But this has been proceeding on a broad front; the difficulties encountered have not been great enough to discourage the pioneers. Indeed, the amount of labor expended on local or regional investigations into problems of historical demography beggars description: antiquaries and genealogists, statisticians and students of medical history, sociologists and economic historians have combed thousands of records and accumulated mountains of quantitative as well as symptomatic evidence regarding past populations.