The cyber domain is undergoing extraordinary changes that present both exceptional opportunities to and major challenges for users of cyberspace. The challenges arise from the malevolent actors who use cyberspace and the many security vulnerabilities that plague this sphere. Exploiting opportunities and overcoming challenges will require a balanced body of knowledge on the cyber domain. Cyberpower and National Security assembles a group of experts and discusses pertinent issues in five areas. The first section provides a broad foundation and overview of the subject by identifying key policy issues, establishing a common vocabulary, and proposing an initial version of a theory of cyberpower. The second section identifies and explores possible changes in cyberspace over the next fifteen years by assessing cyber infrastructure and security challenges. The third section analyzes the potential impact of changes in cyberspace on the military and informational levers of power. The fourth section addresses the extent to which changes in cyberspace serve to empower key entities such as transnational criminals, terrorists, and nation-states. The final section examines key institutional factors, which include issues concerning governance, legal dimensions, critical infrastructure protection, and organization.Cyberpower and National Security frames the key issues concerned and identifies the important questions involved in building the human capacity to address cyber issues, balancing civil liberties with national security considerations, and developing the international partnerships needed to address cyber challenges. With more than two dozen contributors, Cyberpower and National Security covers it all.