Federal Bureau of Investigation
Fbi: Terrorism
FBI's detailed web page with links to information on terrorism and counterterrorism including threat levels, major cases, Most Wanted list, and other resources.
Council of Foreign Relations
Terrorism Questions and Answers: What Is Terrorism?
Part of an extensive website from the Council on Foreign Relations devoted to understanding all aspects of terrorism and its implications for the United States, this section deals with defining and understanding the different types of...