An Inquiry into the Nature and Causes of the Wealth of Nations
By Adam Smith
The above link is (perhaps ironically) to the free Kindle version of Adam Smith's classic. Unfortunately, Smith can't catch a break. Marx ridiculed him for his comparatively thin insights. Schumpeter did the same. If he can't get respect from the socialists or the capitalists, where is he going to get it?
But of course being cited itself is a form of respect. And anyone who seeks to understand capitalism eventually has to cite Adam Smith, whose 1776 treatise systematically examined the market economy in Industrial England. Smith systematically examines the division of labor in industrial work ("not originally the effect of any human wisdom"); legitimizes the motive of gain as driving the economy ("We address ourselves, not to their humanity, but to their self-love"); recognizes the market as a self-organizing system; takes labor as "the only universal, as well as the only accurate, measure of value" (cf. Marx); and describes the law of supply and demand. He argues that the division of labor is a hallmark of developed societies and less known in primitive ones (cf. Engels but also Durkheim). He theorizes wealth and the role of governments in developing it, including the impact of taxes. And he backs up his points with extensive (and sometimes mind-numbing) statistics.
This is a short review because (a) I'm not an economist and (b) I've read and reviewed authors who responded to Smith's ideas. But that doesn't mean this is an unimportant book—it's enormously influential and well worth reading. Or at least skimming.