The United States Border Patrol (USBP) has a long history as our nation's first line of defence against unauthorised migration. Today, the USBP's primary mission is to detect and prevent the entry of terrorists, weapons of mass destruction and illegal aliens into the country, and to interdict drug smugglers and other criminals along the border. This book examines U.S. border security roles and issues including USBP's biometric database of illegal aliens and the FBI's biometric database of criminals and terrorists; the number of unauthorised aliens who die attempting to enter the country each year; the increasing attacks on Border Patrol agents and the threat posed by terrorists along the sparsely defended northern border as well as the more porous Southwest border.