Contemporary security has expanded its meaning, content and structure in response to globalisation and the emergence of greatly improved world-wide communication. The protocols of modern warfare, including targeted killing, enhanced interrogations, mass electronic surveillance and the virtualisation of war have changed the moral landscape and brought diverse new interactions with politics, law, religion, ethics and technology. This book addresses how and why the nature of security has changed and what this means for the security actors involved and the wider society. Offering a crossdisciplinary perspective on concepts, meanings and categories of security, the book brings together scholars and experts from a range of disciplines including political, military studies and security studies, political economy and international relations. Contributors reflect upon new communication methods, postmodern concepts of warfare, technological determinants and cultural preferences to provide new theoretical and analytical insights into a changing security environment and the protocols of war in the 21st century. A useful text for scholars and students of security studies, international relations, global governance, international law and ethics, foreign policy, comparative studies and contemporary world history.