Academician Koval'chenko is the doyen of Soviet quantitative historians and the mentor of many of them.* While the sheer volume of Koval'chenko's publications is due to his erudition and energy, some credit for the increasing sophistication of his work should go to his collaborators and first of all to L. I. Borodkin, who was initially trained in information science. The article published here is the culmination of a series, each more sophisticated than the last, devoted to the agrarian typology of prerevolutionary Russian provinces. The categorization itself holds no great surprises. It corresponds to the authors' earlier findings and, in general, to the common usage of social scientists. The importance of the article lies in showing the extent to which a province matches a particular type and, more particularly, the social and economic determinants of the agrarian development of provinces and types of provinces. Like Selunskaia, Koval'chenko and Borodkin emphasize the sway of the peasantry in prerevolutionary agriculture; indeed, what they now call the "manorial-peasant type" they once called simply the "manorial type." Yet they also bring out the viability, in some regions, of the development on a manorial or "Prussian" basis. In analysis of the kind they undertake, gains in sophistication mean losses in transparency, as more and more operations are performed behind the scenes, usually in the bowels of a computer.t One turns alrmost with relief to the wearying rows of numbers in their appendix, which represent the absolute values for each province that were the point of departure for their analysis; one-third of the rural population in Iaroslavl' Province was literate in 1897-there is a fact to sink your teeth into. Some years ago, Lawrence Stone wondered whether "the sophistication of...mathematical and algebraic formulae are [sic] not ultimately self-defeating, since they baffle most historians." He went on to complain of "the virtual impossibility of checking up on the reliability of final results, since [one] must depend not on published footnotes but on privately owned computer tapes..." t There is no reason to share Stone's disdain for what he cannot bother to understand. We can, however, share his nostalgia for an era, extending from the time of Gibbon until very recently, when all historians could adhere to a common standard of verification. The humble footnote was the basis of the comity of scholars. Koval'chenko, Borodkin and their colleagues explain what they are doing with admirable patience, they share their data with rare generosity, but they are increasingly obliged to characterize their data and the operations they perform rather than identify them, as historians used to do. We can directly verify their findings only by retracing step by step the arduous path of data collection and analysis that they travelled. Perhaps the lesson for historians is that humility and caution become ever more important as our methods become more complex.