Which economist introduced the idea of comparative advantage in an 1817 book?

David Ricardo introduced the idea of comparative advantage in his 1817 book, On the Principles of Political Economy and Taxation.

Comparative advantage explains why trade can benefit two countries even when one is more productive at making every good. A country should specialize in goods it can produce at the lowest opportunity cost, then trade for other goods. Ricardo illustrated the principle with England and Portugal, using cloth and wine as examples.

The idea emerged amid debates over Britain’s Corn Laws, which restricted grain imports and raised food prices. Ricardo argued that international specialization and freer trade could increase overall production and improve economic welfare.

A common mix-up is confusing comparative advantage with absolute advantage. Absolute advantage means producing more efficiently in absolute terms; comparative advantage depends on what must be sacrificed to produce something else. The theory remains a foundation of international economics, although modern trade also considers technology, institutions, transport costs, and distributional effects.