This is both a casebook on U.S. government anti-terrorism criminal enforcement practice and policy, and a volume for teaching a specialized criminal law and procedure course. It provides an in-depth treatment of the major issues that arise in terrorism investigations and in civilian and military terrorism prosecutions. It addresses in detail topics relating to the Guantanamo detention facility and the extended detention of persons suspected of terrorism. Inter alia, it highlights differences in the rules applied in civilian terrorism cases with those used in ordinary crime matters as well as in military commission processes. This edition includes the latest cases, statutes and executive orders regarding subjects like electronic surveillance under the Foreign Intelligence Surveillance Act and its amendments; interrogation practice that led to the torture controversy as well as under the latest FBI interrogation rules; the use of national security letters, and pro-active surveillance by the FBI and drone-targeted killing policy. It includes many extended notes, for example, on relevant changes effected by the Obama administration and actions taken during the first year under President Trump.