The U.S. economy is dependent on the expeditious flow of millions of tons of cargo each day. Cargo containers are an important instrument of global trade but also can present security concerns. U.S. Customs and Border Protection (CBP), within the Department of Homeland Security (DHS), is responsible for administering container security programs, and its strategy for securing maritime cargo containers includes analyzing information to identify shipments that may contain terrorist weapons or other contraband. Because CBP has insufficient resources to examine every container, targeters use Automated Targeting Systems (ATS) to profile which container shipments should be examined. This book addresses how ATS supports CBP's targeting of maritime cargo container shipments for national security purposes; and the extent to which CBP assesses the effectiveness of ATS's national security targeting rules.