Terrorist threats take the form of kidnappings, bombings, assassinations, harassment, propaganda, and a multitude of related activities and indications of potential activity. The vulnerability of the potential targets of these threats must be constantly reassessed. Threat and vulnerability assessment must be developed into a format that matches precise, objective threat analysis with precise, objective vulnerability assessment. The following methodology produces a system for determining the seriousness of the threat of terrorism. The analysis format includes both worldwide and local situation assessments and the listing of all possible threats that could be directed against the area of protective responsibility. The vulnerability assessment focuses on the assessment of potential and probable victims based on the history of threats, current threats, intelligence information, and victim profiles. Protective resources in both public and private sectors should be taken into account. Finally, a threat profile can be created by matching threats and victims and by conducting a vulnerability assessment of the threat-target relationship. The report also discusses international terrorism and international terrorist groups in order to illustrate the practicality of the methodology. To implement the methodology, those charged with the task must study terrorists, their tactics, and their propaganda. A formal and permanent structure for gathering, evaluating, and disseminating the gathered data must be created. Propaganda of radical groups not directly linked to terrorist groups as well as terrorist literature should be analyzed since the radical press often influences terrorist strategies and actions. A sample fault tree, which provides a visible representation of the relationship of threat and victim by detailing all the ways of carrying out the identification action, is provided, as are other methods of expressing the threat-victim relationship. Tabular data and footnotes are included.