Arquilla was one of the first analysts to appreciate how digital technologies were transforming the nature of conflict, and he remains one of the most perceptive. His latest book pulls together the strands of his three decades of studying this issue. A constant theme is frustration at the failure of policymakers to adjust their thinking, despite his own efforts to advise and inform them. It took too long for them to appreciate the vulnerability of computer networks to crooks and hostile political actors. Companies and governments placed too much emphasis on firewalls and antivirus software when encryption and cloud computing offered better defenses. In addition, because military planners were reluctant to abandon the legacy systems of industrial age warfare, such as tanks, they failed to notice the potential of tactics involving numerous small units, in constant communication with one another, overwhelming targets in swarms—a form of warfare that Arquilla dubs “bitskrieg.” One distinctive feature of his approach is his belief in arms control agreements to ensure that civilians and critical infrastructure are spared harmful attacks. Sadly, despite some occasional high-level interest, there have been no serious negotiations on that issue among the major powers.