Today marks the date in 1968 that sixty-one nations, including the United States, Britain and the Soviet Union, signed the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) which set up systems to monitor use of nuclear technology and prevent more nations from acquiring nuclear weapons. The treaty went into force in 1970. 190 countries are now signatories; Israel, India and Pakistan remain outside the Treaty. North Korea joined the NPT in 1985, but in January 2003 announced its intention to withdraw from the Treaty.
A history and description of the NPT is also offered on these websites:
Deanna Dee-Dee Taylor 