William Playfair (1759 - 1823) was a Scottish engineer and political economist, who in 1805 published: "An Inquiry Into the Permanent Causes of the Decline and Fall of Powerful and Wealthy Nations."the 'Inquiry* embraces a considerable extent of historical detail, as well as political and economical investigation. Wealth and power form the criterion, by which the prosperity of nations is usually estimated: with what propriety, we cannot now stop to inquire. These advantages have been found to/be as precarious in the possession of nations, as they are in that of individuals. Like the tide, they flow only to ebb again; for they naturally excite, in those who enjoy and in those who want them, dispositions little calculated to fix them in a permanent abode. These dispositions are to be considered as the moral springs of those operating causes, by which they are transferred from one people to another. To discover the nature of the causes thence arising, and the means by which their effects may be avoided, the author reviews the history of those countries in which their agency has been the most evident.The space surveyed is divided into three periods, each of which is characteristically different from the others. The first is, that, prior to the fall of the Roman Empire, during which, national opulence and influence were generally transferred by amis; the second, that which succeeded, till the discovery of America and of the passage to the East Indies by the Cape of Good Hope, in which national elevation followed the more gentle fluctuations of commerce; and the third, that which comes down to present times, not inferior in importance to either of the preceding, in which the features of the two former have been combined, and their consequences transferred to new possessors, by means of three, nearly contemporary discoveries in the arts; those of the magnetic power of the needle, of printing, and of gunpowder. The moral as well as political effects produced in the state of mankind, by these advances in science, are incalculable; and their influence will be felt through every successive age, till the ultimate designs of Providence, with regard to the human race, have received their full accomplishment. Whether any other operating cause, destined to produce such further effects on the state of mankind, as shall form a new epoch in their history, remains yet undeveloped, the progress of time will reveal.From the data furnished by a survey of past periods, the author deduces the causes which have, in a great degree, been common to the several changes enumerated, and which he consequently infers to be general causes producing such effects, although in a way not at all times similar. These he divides into two principal classes, internal and external. There is a third class which may be termed accidental, but which, from its nature, requires little attention in a philosophical investigation of general causes.