The U.S.-Mexico and U.S.-Canada borders are the two busiest land crossings in the world. Canada and the United States are each other''s largest trading partners and Mexico is America''s second largest trading partner with trade between the two nations more than tripling since the start of NAFTA. The many immediate ripple effects of the terrorist attacks on the World Trade Center and the Pentagon included a dramatic tightening of North American border controls and a hardening of the policy discourse about cross-border flows. This is the first book that explores the implications of September 11th and the new war on terrorism for border controls, cross-border relations, and economic integration in North America. The volume makes a unique contribution to important scholarly and policy discussions over the meaning and management of borders in an increasingly borderless (regional and global) economy, and adds fuel to broader debates over the changing nature of borders and territorial politics in a radically transformed security environment.