No single nation, culture or religion can achieve peace and security at home while ignoring the terrorist threats posed to others globally. This book presents lectures and a keynote speech delivered as part of the NATO Advanced Training Course (ATC) Countering ISIS Radicalisation in the Region of South-East Europe (CIRACRESEE), held in Ohrid, Republic of Macedonia, in April 2017. The main objective of the five-day ATC was to provide participants from the integrated security sector with information and knowledge about global trends with regard to the uses of cyberspace by ISIS, as well as accentuating the importance of the resulting social and technological challenges. An in-depth analysis of how these trends are influencing the region was also performed. The course topic was addressed from strategic/political, legal and technical perspectives, and participants were engaged in creating future regional policy proposals to counter ISIS use of cyberspace by engaging political, strategic, legal and technical components. The 12 selected lectures presented here provide readers with a comprehensive analysis from a socio-cultural, organizational and technological perspective. Among the authors are well-known academics and security professionals with internationally proven expertise in their areas of work, and the book will be of interest to all those working in the field of counter-terrorism.