Fernando Reinares is a specialist in terrorism, especially the process of radicalization; currently is Professor of Political Science and Security Studies at Universidad Rey Juan Carlos in Madrid. After serving a term as Senior Adviser on Antiterrorist Policy to the Spanish Minister of Interior following the 2004 Madrid bombings, engaged in adapting national security structures to the challenges of international terrorism, he was appointed Director of the Program on Global Terrorism at the Real Instituto Elcano, a Spanish think tank. He also teaches postgraduate courses at General Gutiérrez Mellado University Institute and Ortega y Gasset University Institute.
Advisor to the Center for Global Counter Terrorism Cooperation, he belongs to the United Nations roster of experts on terrorism prevention and the terrorism studies programme board at the University of St. Andrews. Reinares is a member of the Council on Global Terrorism established by the Atlantic Monthly Foundation and of the academic committee of the Queen Sofía Center for the Study of Violence. He is Chairman of the European Commission expert group on violent radicalization, and Academic Director of the Permanent Seminar on Terrorism Studies at Ortega y Gasset Foundation.
He is a Contributing Editor to Studies in Conflict and Terrorism, and belongs to the editorial boards of Terrorism and Political Violence, Democracy and Security, Cultures et Conflits and Sécurité Globale.
He has been invited to join the Woodrow Wilson International Center for Scholars in Washington, D.C., as Public Policy Scholar in 2011.
Defining terrorismTo analyze anything, one must define the problem. In the main terrorism article, this is distinctly difficult. A 2005 paper by Reinares establishes subsets for discussion.
International terrorism is not exactly the same thing as transnational terrorism. Neither should international terrorism be confused with Islamist terrorism, even though these terms refer to phenomena that at present largely overlap.
- "Transnational terrorism in one way or another crosses state borders, essentially because those who perpetrate it maintain organizational structures or carry out violent activities in more than one country, generally including territories over which the authorities to whom their demands are directed have no jurisdiction." Alternatively, it may involve situations where the authorities have an international role, such as Spanish involvement in the Iraq War.
- Transnational terrorism includes international terrorism but not vice-versa.
- As a first requirement, international terrorism is "practiced with the deliberate intention of affecting the structure and distribution of power in entire areas of the world and even at the level of global society itself. Second, the individuals and groups who carry it out have extended their activities to a significant number of countries and geo-political regions, in accordance with their declared aims." The second condition is necessary for actions to be international.
- He describes Islamist international terrorism is a primarily Salafist phenomenon "at the regional or local level, who either originate in al-Qaeda or take this organization as their point of reference..." This is "the fourth wave of modern insurgent terrorism, although for more than ten years now there exists a new kind of Islamist terrorism, distinct from other immediately preceding versions of this type of violence also practiced by Muslim fundamentalists: Shiites sponsored by Iranian theocrats and Syrian government agencies, among others."
- Not all Islamist terrorism is international, even though it may be transnational. "Hamas, whose wide range of activities is broadly transnationalised, has repeatedly attacked Israeli interests and citizens... as a way to work towards the founding of an independent Palestinian state, like other terrorist organizations, both secular and religious in inspiration, based in the occupied territories. However, as far as is known to date, no formal links or strategic harmony have been established between these terrorist groups and al-Qaeda or with any of its affiliated bodies.
Analysis of 2004 terrorists
Most of the participants in the 2004 Madrid bombings were first thought to involve self-radicalization, but, according to Reinares, now appears that most were radicalized before the 9-11 Attacks and the Iraq War, but the actual group coalesced in Spain. Most were economic immigrants although one was a native Spaniard. Internet access complemented face-to-face group formation, allowing downloading of such things as the works of Sayyid Qutb and Abdullah Azzam.  Indeed, "a gradual sense of progressive involvement, usually considered a consistent quality among those becoming terrorists, seems to be absent for some latecomers in the Madrid bombing network. 
- Fernando Reinares (9 January 2005), Conceptualising International Terrorism, Real Instituto Elcano, Area: International Terrorism - ARI Nº 82/2005 (Translated from Spanish)
- Fernando Reinares (November 2009), "Jihadist Radicalization and the 2004 Madrid Bombing Network", CTC Sentinel, Combating Terrorism Center, United States Military Academy 2 (11), pp. 16-19
- John Horgan, “From Profiles to Pathways and Roots to Routes: Perspectives from Psychology on Radicalization into Terrorism,” Annals of the American Academy of Political and Social Sciences 618:1 (2008): pp. 80-93, cited by Reinares 2009