This book is a suite of articles, studies, and scientific papers on the "hybrid conflict" topic. This type of conflict is present in literature, especially in the military, since 2004, when it first appeared in American writings. Ten years later, Russia successfully implemented the concept in its actions such as the annexation of Crimea and the aggression of Ukraine, after practicing various combinations in Georgia and Estonia. The concept of hybrid war describes the mix of conventional, unconventional and irregular components that combine into unique forms and in all confrontational environments. In this context, the book addresses aspects such as: the role of information in the decision-making process, the importance of applying critical and creative thinking in planning operations, ways to prepare for military operations and, of course, the consequences and repercussions of the phenomenon in the security environment that generated changes and adaptations of strategies at the national level (the case of Romania), at the level of the European Union and NATO.