Adam Smith published An Inquiry into the Nature and Causes of the Wealth of Nations in 1776, and the book has shaped economic thought for the two and a half centuries since. The famous phrases people half-remember, the invisible hand and the division of labor, both come from this text, though both are more nuanced in context than the cliches suggest.
The book is long. Smith covers everything from the pin factory and labor specialization to monetary theory, taxation, the operations of joint-stock companies, and the proper role of government. He is more critical of merchants and landlords than libertarian readings of him often acknowledge.
Reading the original is a different experience from reading summaries. Smith’s prose is dense but rewarding. The eighteenth century rhythm takes some adjustment.
For anyone serious about economics, political philosophy, or intellectual history, this is foundational reading. Pair it with The Theory of Moral Sentiments, his earlier and shorter work, for the fuller picture of his thought.