The world in which we live today is becoming more and more complex, both from the viewpoint of ensuring security as well as of the strong dependence of the social community on technology, which is represented by so-called critical infrastructure. We are surrounded by a dynamic security environment in which we witness various security threats and risks - which even yesterday still seemed marginal. International terrorism is much overlooked and represents one of the most important threats for a normal functioning of the modern democratic society and its values. In the period after the terrorist attack in the United States of America (USA) we have witnessed the so-called anti-terrorism war, which has not managed to eliminate or lessen the reasons for emerging and establishing new terrorist networks.

When these factors are put into the context of the development of modern technology, we can see that the provision of security against terrorist threats is extremely difficult. Despite the efforts of national security entities in the national and international context, terrorist threats are not completely preventable. This means that it is necessary to prepare the functioning of the system, starting from the wider social community response to the occurrence of a terrorist attack, to an extent that it will quickly and effectively operate even in this type ofcrisis.

The coordination of authorities and services responsible for the first response in the event of a terrorist act is one basic requirement, which can significantly contribute to a more effective response and reduction of adverse effects. Of course, the economic and financial crisis puts us all in the position that would in the long term entail a reduction of resources for the functioning of the national security system and thus less efficient functioning of those parts of the system that are designed to respond to crisis first. On the other hand, every crisis can be an opportunity to achieve a more rational look at the system as a whole and critically define the role of each individual segment. Through a thorough analysis of national security systems, conducted after 11 September 2001, the main findings were primarily focused on the lack of coordination, duplication of responsibilities, non-systemic approaches and the capability development in the field of countering complex threats, which certainly include international terrorism. A few steps towards improving coordination and concerted action have definitely been done, but still not enough.

Due to rapidly changing environment and related forms of individual threats, which are increasingly moving into the cyber environment, the national security systems, which in many cases are burdened with bureaucratic approaches to changes, face great difficulties in monitoring this dynamics. In this respect, the largest problem lies in the countries which have luckily not yet been submitted to major terrorist threats, but are, due to this virtual safety, responding to terrorist risk much slower than other countries. In a mutually interdependent environment this can become a serious problem, since international terrorism knows no borders and in such environments, it benefits from exploiting the lack of system control measures. In the international community, it has long been recognized that an effective system of international response to terrorist threats can only be successful as much as individual countries, including those less well prepared. From this perspective, the above-mentioned crisis can be considered an advantage, in the sense that we are forced to respond more rationally to the structuring of the national security system and thus eliminate barriers of cooperation between line ministries, which just yesterday seemed insurmountable. The realization that the bodies of national security system are no longer a sufficient condition for a successful functioning of the counter-terrorism system is also strongly enforced. This process certainly requires the inclusion and participation of other non-state actors, which are developed in the framework of private and corporate security sector. To respond effectively to terrorist threats, it is important to mobilize a comprehensive range of levers, not necessarily of state character. The development of public and private partnerships is increasingly penetrating even to the area of security, thus these processes need to be seriously taken into account in building a stronger and more efficient system. If, however, this framework includes threats by individual terrorist groups to use the means of mass destruction, we see that effective participation of the full range of bodies and organizations is the key factor, which in the phase after a terrorist act, sufficiently maintains the effects of such an act at an acceptable level. Of course, there is always a dilemma, which is the acceptable level of risk management, because every human life is invaluable. However, as a suitable level one should look for a critical point that has to be attained for the society to establish normal functioning as soon as possible, despite a crisis situation.

Terrorist attacks do not only cause material damage; their effect is especially problematic from a psychological perspective. From this perspective, an effective system of responding to terrorist threats should not only include initial emergency measures to reduce damage to property and protect human lives, but should continue through later stages of managing post-traumatic disorders of individuals in a wider social environment. With the development of information and other technologies, the society has become complex and vulnerable. We live in an increasingly high-risk society. The positive aspects of development also bring several strongly negative consequences that can, in their extreme form, present an increasing threat to individual, national or international security. The remarkable development of technology has certainly facilitated progress in all segments of the functioning of the society. However, on the other hand, the dependence of the society on the functioning of technological systems is strong; a minor system malfunction might have important consequences for the functioning of the society. For this reason, the reliance on the functioning of this infrastructure has obvious direct and indirect impacts on its threat and represents a tempting target for international terrorist operations.

Due to the obvious interdependence, terrorist operations, which used to have local dimensions in the past, are now taking on new regional and global dimensions. The complexity of international relations and the functioning of the international system make national security systems interact with the regional and international environment. In fact, contemporary terrorism has helped the regional community recognize it as a regional phenomenon that requires regional response at different levels. Since terrorist activities are not confined to national borders, the international community can fight terrorism effectively only with the improvement of measures in the area of cooperation, organisation, solidarity between countries, initiatives combining different strategies and mechanisms, and specifically with an increased exchange of information that are important for countering this regional problem. That was one of the main goals of this NATO Advanced Research Workshop “Managing Terrorism Threats to Critical Infrastructure – Challenges for South Eastern Europe”, which was held in Belgrade, Serbia in 2014. The participants from fifteen NATO and partner countries and three international organisations had the opportunity to share their knowledge and experiences on the future improvement of critical infrastructure protection from various terrorist threats. At the same time a collaborative link between scientists and specialists in the region was created. This network of stakeholders will foster further collaborations and the exchange of ideas regarding critical infrastructure protection from terrorist attacks.

In this book, we presented and pointed out authors' main dilemmas and challenges that might influence the process of managing terrorist threats in the region of SEE. It also helps uncover a part of challenges which the complex security environment with its threats brings to the subjects of national, regional, as well as international security in South Eastern Europe.

In the end Editors, on their behalf and on the behalf of all authors, express their deep gratitude to NATO Emerging Security Challenges Division for the moral professional and financial support, which made possible organization of this event. The Editors wish to acknowledge with appreciation the assistance of Dr. Iztok Podbregar and Dr. Anita Perešin in reviewing the manuscripts for this publication.

Dr. Denis Čaleta

Institute for Corporative Security Studies

Dr. Vesela Radović

Faculty of Applied Security, University Educons