An introduction to globalization, economic integration, and international trade by defining key concepts and explaining why countries trade based on specialization, opportunity cost, and comparative advantage. It highlights both the benefits, such as innovation, peace, and economic efficiency, and drawbacks, including income inequality and industry disruption. Drawing from Doug Irwin’s work, it outlines three core trade policy principles: import taxes effectively tax exports, businesses rely on imports too, and trade imbalances reflect underlying capital flows tied to savings and investment, not merely trade policies.