The Tallinn Manual on the International Law Applicable to Cyber Warfare, written at the invitation of the Centre by an independent International Group of Experts, is the result of a three-year effort to examine how extant international law norms apply to this new form of warfare. The Tallinn Manual pays particular attention to the jus ad bellum, the international law governing the resort to force by States as an instrument of their national policy, and the jus in bello, the international law regulating the conduct of armed conflict (also labelled the law of war, the law of armed conflict, or international humanitarian law). Related bodies of international law, such as the law of State responsibility and the law of the sea, are dealt within the context of these topics. The Tallinn Manual is not an official document, but instead an expression of opinions of a group of independent experts acting solely in their personal capacity. It does not represent the views of the Centre, our Sponsoring Nations, or NATO. It is also not meant to reflect NATO doctrine. Nor does it reflect the position of any organization or State represented by observers.