No lawyer or business operating in North America can escape the significance of NAFTA and its successor, the USMCA. This Nutshell introduces students, lawyers, government officials, and businesspersons to the law and economics of North American free trade. It first examines the basic question: Why Trade at All? The origins, rules, operation, and impact of NAFTA and its environmental and labor side agreements since 1994 follow. Changes made in the 2020 USMCA agreement and their early impacts upon business are explored in detail. In preparing this Nutshell, we have attempted to address the interests not only of North Americans, but also persons located outside the region who are concerned about the externalities of North American free trade, intellectual property rights, and foreign investment.