THE ROOT OF modern terrorism go back to late 19th century, but at the threshold of the 21st century this phenomenon has reached unprecedented proportions and has become a menace to civilized societies worldwide. Essentially, terrorism is a tool of warfare. It uses intimidation and fear to achieve national, social or religious objectives and it rests on clearly articulated philosophies about its effectiveness. As a highly accessible tool, terrorism is available for anyone to use,  be it sub-state entities, states, or individuals (e.g. the Unabomber, or Igal Amir—Itzhak Rabin’s assassin). One must not necessarily expect that the users of terrorism would possess profound common psychological or sociological characteristics. Members of the Bader Meinhoff faction in Germany, need not resemble in psychological make up members of the Al Quaeda network, or members of other terrorist organizations. Rather the hope of understanding the psychology of terrorism should, probably, rest on the psychology of means deployment. Under what conditions would individuals or groups deploy a given means to  their objectives? This approach distinguishes between terrorism as a tool (with its own developmental history, philosophy, and operational logic) and terrorists as diverse potential users of this tool. In my own studies of terrorism, I have attempted to address this and other socio psychological issues, including suicide terrorism, individual versus organizational aspects of terrorism, and terrorism as a tool of minority influence. My involvement in terrorism studies dates back to the year 2001 when I was appointed member of the National Academies of Science panel on the social and psychological aspects of terrorism. After an intense research activity that lasted till late 2002, we have produced two extensive reports on this topic published by the National Academies Press, and titled “Discouraging terrorism: some implications of 9/11”, and “Terrorism: Perspectives from  the behavioral and social sciences”. In 2003, I was appointed to a National Academies team to conduct a workshop commissioned by the Department of Homeland Security (DHS) on the “Frameworks for Higher Education in Homeland Security” culminating in a published document under this title. Finally, I have been appointed as co-director of the Center of Excellence for Research on the Behavioral and  Social Aspects of Terrorism and Counterterrorism, sponsored by the DHS. This Center  consists of a consortium of researchers from various national and international universities under the leadership of the University of Maryland in College Park. With the research talent and the resources at our disposal we hope to launch an unprecedented foray into the social and behavioral factors in terrorism.  We expect to offer not only empirically based, and theoretically sound insights into this disturbing phenomenon, but also concrete recommendations about ways of counteracting it.