Revisionism usually supplies whatever excitement there is to be found in writings on dogmengeschichte. Here, achievement often consists in showing that a writer had been badly misinterpreted, or that his contribution is far greater than is generally supposed. This paper can, however, pretend to propose no more than a modest revision of our ideas on the early writings on Say's Law. It will be argued that J. B. Say and his contemporary James Mill, who is also sometimes credited with the notion that "supply creates its own demand", really seem to have had in mind a set of ideas rather more complex than that and, moreover, that the main policy implications they drew from their discussion went well beyond the comforting thought that fears of universal glut are baseless. Certainly, their discussion was not Panglossian in spirit, for one of their main points was the superiority, from the point of view of growth in economic welfare, of investment outlays over idle consumption (either in the form of luxurious living by wealthy individuals or the military and other unproductive outlays of prodigal governments). Moreover, these authors maintained that only production can create real purchasing power, so that an impecunious community is in no position to provide effective demand in abundance. Restriction in output must necessarily limit effective demand and is certainly not a way to promote it, particularly in the long run. These are ideas, it will be noted, that the modern literature does not reject, at least not with the universality with which it denies the notion that supply creates its own demand. Indeed, they are thoughts that may still be of some pertinence, particularly for development theory and policy. Moreover, for the time in which these authors were writing, these ideas can certainly not be considered a manifestation of conservatism. Rather, they can be interpreted as a reply to the defenders of the landed aristocracy and their consumption patterns, and as support for the expanding spirit of capitalist enterprise that accompanied the young industrial revolution. Obviously, there is no limit to the extent to which one can subdivide the notions composing Say's discussion of markets or exchanges (debouches), his related remarks on consumption, or the parallel materials in Mill. I will confine myself to those relationships that have played a substantial role in later discussions, particularly in recent literature, and to those observations that seem clearly to have been uppermost in the minds of the authors as indicated by the degree of emphasis devoted to them. But before getting to that, it is appropriate first to recapitulate the contents of Say's Law, as it is understood nowadays, and as contrasted with the main proposition espoused by Say himself.