'The Wealth of Nations, Book 4' Summary

Book IV: Of Systems of political Economy

Smith vigorously attacked the antiquated government restrictions he thought hindered industrial expansion. In fact, he attacked most forms of government interference in the economic process, including tariffs, arguing that this creates inefficiency and high prices in the long run. It is believed that this theory influenced government legislation in later years, especially during the 19th century.

Smith advocated a government that was active in sectors other than the economy. He advocated public education for poor adults, a judiciary, and a standing army—institutional systems not directly profitable for private industries.

Of the Principle of the Commercial or Mercantile System: The book has sometimes been described as a critique of mercantilism and a synthesis of the emerging economic thinking of Smith's time. Specifically, The Wealth of Nations attacks, inter alia, two major tenets of mercantilism:

1. The idea that protectionist tariffs serve the economic interests of a nation (or indeed any purpose whatsoever) and
2. The idea that large reserves of gold bullion or other precious metals are necessary for a country's economic success. This critique of mercantilism was later used by David Ricardo when he laid out his Theory of Comparative Advantage.

Of Restraints upon the Importation: Chapter 2's full title is "Of Restraints upon the Importation from Foreign Countries of such Goods as can be Produced at Home". The "invisible hand" is a frequently referenced theme from the book, although it is specifically mentioned only once.

"As every individual, therefore, endeavours as much as he can both to employ his capital in the support of domestic industry, and so to direct that industry that its produce may be of the greatest value; every individual necessarily labours to render the annual revenue of the society as great as he can. He generally, indeed, neither intends to promote the public interest, nor knows how much he is promoting it. By preferring the support of domestic to that of foreign industry, he intends only his own security; and by directing that industry in such a manner as its produce may be of the greatest value, he intends only his own gain, and he is in this, as in many other cases, led by an invisible hand to promote an end which was no part of his intention. Nor is it always the worse for the society that it was no part of it. By pursuing his own interest he frequently promotes that of the society more effectually than when he really intends to promote it." (Book 4, Chapter 2)

The metaphor of the "invisible hand" has been widely used out of context. In the passage above Smith is referring to "the support of domestic industry" and contrasting that support with the importation of goods. Neoclassical economic theory has expanded the metaphor beyond the domestic/foreign manufacture argument to encompass nearly all aspects of economics.

Of the extraordinary Restraints: Chapter 3's long title is "Of the extraordinary Restraints upon the Importation of Goods of almost all Kinds, from those Countries with which the Balance is supposed to be Disadvantageous".