According to the FBI about 4000 ransomware attacks happen every day In the United States alone victims lost 209 million to ransomware in the first quarter of 2016 Even worse is the threat to critical infrastructure as seen by the malware infections at electrical distribution companies in Ukraine that caused outages to 225000 customers in late 2015 Further recent reports on the Russian hacks into the Democratic National Committee & subsequent release of emails in a coercive campaign to apparently influence the US Presidential Election have brought national attention to the inadequacy of cyber deterrence The US government seems incapable of creating an adequate strategy to alter the behavior of the wide variety of malicious actors seeking to inflict harm or damage through cyberspace This book offers a systematic analysis of the various existing strategic cyber deterrence options & introduces the alternative strategy of active cyber defense It examines the array of malicious actors operating in the domain their methods of attack & their motivations It also provides answers on what is being done & what could be done by the government & industry to convince malicious actors that their attacks will not succeed & that risk of repercussions exists Traditional deterrence strategies of retaliation denial & entanglement appear to lack the necessary conditions of capability credibly & communications due to these malicious actors' advantages in cyberspace In response the book offers the option of adopting a strategy of active cyber defense that combines internal systemic resilience to halt cyber attack progress with external disruption capacities to thwart malicious actors' objectives It shows how active cyber defense is technically capable & legally viable as an alternative strategy for the deterrence of cyber attacks