Some of the fringe benefits of experience are memory and the opportunity to indulge that faculty in writing the preface to a book of this nature. A few decades ago the hope was that social scientists would, by their mastery of statistical methodology, succeed in laying bare the facts and forces that drive social systems. The economists set the pace, for these were the years of the great macroeconometric models – in the later years of their evolution, gargantuan structures with hundreds of equations tended by a small army of priests and acolytes. We had high ambitions in those days, even if reality all too often had to be uncomfortably bought off. Thus the aim was to produce an explanation (in, e.g., a regression context) in which all systematic influences were to be accounted for and the residual to be unstructured white noise; but if the latter were not immediately available, one simply transformed the equation to get it, invoking ritual incantations of habit formation, partial adjustment mechanisms, and the like. Later it was held to be unrealistic to attempt to capture every possible systematic influence. Perhaps serial correlation or heteroscedasticity in our residuals might after all be allowable if one recognized it, hopefully could justify it, and certainly could design one's regression methodology to cope with it.