In a world with almost limitless data collection capability, where cyberattacks can propagate instantaneously and where the identity or location of an adversary may not be known, individuals and institutions are increasingly vulnerable to cyberattacks that disrupt productivity, jeopardize privacy, and threaten national security. This course examines legal, business, and policy challenges stemming from rapidly evolving cybersecurity threats. It begins with an introduction to cybersecurity, cybercrime, and cyberwarfare. It explores the national and international legal frameworks that govern cyberspace, including laws related to cyber crime, espionage, and war. The course also discusses how current laws affect corporations and provides detailed case studies regarding the state of cybersecurity in various countries. It looks at the limits of current law and the need for further policy evolution, as well as the real-world impact of different legal, business, and policy options.