The purpose of this study is to focus attention on the types of individuals and groups that are prone to terrorism (see Glossary) in an effort to help improve U.S. counter terrorist methods and policies.The emergence of amorphous and largely unknown terrorist individuals and groups operating independently (freelancers) and the new recruitment patterns of some groups, such as recruiting suicide commandos, female and child terrorists, and scientists capable of developing weapons of mass destruction, provide a measure of urgency to increasing our understanding of the psychological and sociological dynamics of terrorist groups and individuals. The approach used in this study is twofold. First, the study examines the relevant literature and assesses the current knowledge of the subject. Second, the study seeks to develop psychological and sociological profiles of foreign terrorist individuals and selected groups to use as case studies in assessing trends, motivations, likely behavior, and actions that might deter such behavior, as well as reveal vulnerabilities that would aid in combating terrorist groups and individuals.Because this survey is concerned not only with assessing the extensive literature on socio-psychological aspects of terrorism but also providing case studies of about a dozen terrorist groups, it is limited by time constraints and data availability in the amount of attention that it can give to the individual groups, let alone individual leaders or other members. Thus, analysis of the groups and leaders will necessarily be incomplete. A longer study, for example, would allow for the collection and study of the literature produced by each group in the form of autobiographies of former members, group communiqués and manifestos, news media interviews, and other resources. Much information about the terrorist mindset (see Glossary) and decision-making process can be gleaned from such sources. Moreover, there is a language barrier to an examination of the untranslated literature of most of the groups included as case studies herein.Terrorism databases that profile groups and leaders quickly become outdated, and this report is no exception to that rule. In order to remain current, a terrorism database ideally should be updated periodically. New groups or terrorist leaders may suddenly emerge, and if an established group perpetrates a major terrorist incident, new information on the group is likely to be reported in news media. Even if a group appears to be quiescent, new information may become available about the group from scholarly publications.There are many variations in the transliteration for both Arabic and Persian. The academic versions tend to be more complex than the popular forms used in the news media and by the Foreign Broadcast Information Service (FBIS). Thus, the latter usages are used in this study. For example, although Ussamah bin Ladin is the proper transliteration, the more commonly used Osama bin Laden is used in this study.