International trade is a critical component of the U.S. economy, with U.S. merchandise imports and exports amounting to $2.2 trillion and $1.5 trillion in 2011, respectively. The efficient flow of legally traded goods in and out of the United States is thus a vital element of the country's economic security. U.S. Customs and Border Protection (CBP), within the Department of Homeland Security (DHS), is the primary agency charged with ensuring the smooth flow of trade through U.S. ports of entry. CBP's policies with regard to U.S. imports are designed to: facilitate the smooth flow of imported cargo through U.S. ports of entry; enforce trade and customs laws designed to protect U.S. consumers and business and to collect customs revenue; and enforce import security laws designed to prevent weapons of mass destruction, illegal drugs, and other contraband from entering the U.S. - a complex and difficult mission. This book describes and analyses import policy and CBP's role in the U.S. import process, with a focus on the legislative history of customs laws; "trusted trader" programs to improve enforcement of intellectual property and trade remedy laws, to strengthen cargo scanning practices, and/or to promote modernisation of customs data systems.