This book outlines the main technological, legal, and operational options that liberal democratic nations have when confronting challenges in cyberspace. It offers a range of policy ideas they can adopt to make their defense stronger and deter future cyber-attacks. The author explores how liberal societies, especially those in the Western world, have so far confronted a variety of cybersecurity challenges by hackers in nondemocratic regimes like Russia and China. and zooms in on the main challenges that democratic states face in adopting strategies of cyber deterrence, and how those challenges shape their ability to actually deter hackers.