This document provides an introduction to international economics. It defines trade as the transfer of goods or services in exchange for money. A nation exports surplus goods and services after domestic demand is met, and imports goods and services it cannot meet domestically. International trade differs from internal trade in that it crosses country borders, uses foreign languages and currencies, faces more restrictions and competition, and involves immobile factors of production moving between countries. International trade is important as it provides outlets for surplus production, leads to more efficient allocation of resources worldwide, widens markets, encourages innovation, and has an educative effect.