Is the threat or use of nuclear weapons ever permissible? This question was, at the request of the United Nations General Assembly, put before the International Court of Justice in 1996 for an advisory opinion. An evenly divided Court concluded that ""the threat or use of nuclear weapons would generally be contrary to the rules of international law applicable in armed conflict, and in particular the principles and rules of humanitarian law"" -not an outright condemnation, but certainly strong enough to set in motion the serious initiative to outlaw nuclear weapons currently before the nations of the world.;The Court's advisory opinions are considered non-binding, and yet this is the only statement by the world's highest tribunal on this question. Thus, as the only authoritative pronouncement on the subject, it carries great weight for the future of nuclear weapons and international law itself. In a broader sense, the Court's Opinion has considerable significance regarding the future of the international order and even the survival of humanity.;In an historical context, the authors of this deeply engaged book examine the Court's Opinion and the logic leading to its conclusion. They study the implications of the Opinion for the future of nuclear weapons policy, the law of armed conflict, and the role of the Court's advisory jursidiction, especially on issues that affect the future of humanity. They also study separate and dissenting opinions, as well as the role of citizens groups in bringing this crucial question before the Court.