Missiles came of age after World War II and the United States has pursued missile defences ever since. The issue has turned out to be one of the most divisive of the past generation taking into account the Russian position and their threat or perceived threat and the technical difficulties of actually implementing any missile defence. The Bush Administration claims that for the first time an effective missile defence is technically possible and that the threat of weapons of mass destruction has spread to many nations and groups other that Russia. The two factors, according to them, make missile defence an urgent priority justifying the breaking of the widely-revered ABM Treaties. Their argument rests partially on a bet that the Russians have now fallen so far behind since the Yeltsin government took over that they cannot keep up technologically. Although terrorism groups will not be deterred by the missile defence being planned, countries like China, North Korea etc., might well be. This book frames the current debate and also presents the legal considerations for withdrawal from the ABM Treaties.