When Tom Lehrer sang 'We'll all go together when we go', the world was gripped by fear of nuclear holocaust. With the collapse of the Soviet Union, the threat was assumed to have gone away. But Libya, Iraq, Iran and North Korea and others are building weapons of mass destruction, nuclear, biological and chemical. And terrorists like bin Laden are trying to get their hands on them too. The next live Scud missile launch could signal the next Hiroshima. Russia has enough weapons grade plutonium in poorly guarded facilities to make 20,000 atomic bombs. Osama bin Laden only needs one. Chemical weapons remain the 'poor man's nuke'. Saddam believed his chemical weapons saved him in the first Gulf War. Islamic fundamentalists have been preparing to use ricin for mass poisoning in London. A Japanese doomsday cult used sarin nerve gas on the Tokyo underground. Robert Hutchinson's measured account provides a straightforward guide to the weapons that threaten civilisation.