This study takes a holistic approach to understanding how Russia conducts hybrid warfare against its neighbours states at the interface between East and West. The book examines these countries' vulnerability to Russian influence and hybrid warfare tactics, as well as their responses to this security challenge. It contains a detailed examination of local developments in states such as Ukraine, Belarus, Finland, Armenia, Serbia and many others, analyses specific scenarios and practices, and draws on these observations to develop an up-to-date conceptual understanding of the phenomenon of hybrid warfare. Scholarship often focuses solely on Russia and treats countries exposed to Russian hybrid measures as passive victims, creating an overly simplistic picture of Russian behaviour. This book instead treats these states as independent actors and assesses their potential to address and counter the specific security challenges arising from their geographical and political situation.