Chapter XVI of the Manual deals with the novel topic of cyber operations and Chapter 16 of the book gives appropriate credit to the Manual’s authors for including discussion of this novel and controversial topic. Both Chapters are understandably brief. After considering the Manual’s definition of cyberspace, its explanation of cyberspace operations and its discussion of other preliminary matters, the Chapter tackles the vexed question of the application of the law of war to cyber operations. Cyber operations and the jus ad bellum, cyber operations and the law of neutrality, cyber operations and the jus in bello, and the legal review of weapons that employ cyber capabilities are all then the subject of dedicated sections within the Manual and, this, of the Chapter. While, inevitably, there is a great deal more that could have been said in the Manual on this important and contemporary topic, that which the Chapter sets forth represents a useful expression of the US view.