The national security of the United States depends on a secure, reliable and resilient cyberspace. The inclusion of digital systems into every aspect of US national security has been underway since World War II and has increased with the proliferation of Internet-enabled devices. There is an increasing need to develop a robust deterrence framework within which the United States and its allies can dissuade would-be adversaries from engaging in various cyber activities. Yet despite a desire to deter adversaries, the problems associated with dissuasion remain complex, multifaceted, poorly understood and imprecisely specified. Challenges, including credibility, attribution, escalation and conflict management, remain ever-present and challenge the United States in its efforts to foster security in cyberspace. These challenges need to be addressed in a deliberate and multidisciplinary approach that combines political and technical realities to provide a robust set of policy options to decision makers. The Cyber Deterrence Problem brings together a multidisciplinary team of scholars with expertise in computer science, deterrence theory, cognitive psychology, intelligence studies and conflict management to analyze and develop a robust assessment of the necessary requirements and attributes for achieving deterrence in cyberspace. Beyond simply addressing the base challenges associated with deterrence, many of the chapters also propose strategies and tactics to enhance deterrence in cyberspace and emphasize conceptualizing how the United States deters adversaries.