The Gulf War of 1990-91 saw a real danger that chemical or biological weapons might be used against coalition forces. This authoritative account details the doggedly persistent work of the United Nations Special Commission (UNSCOM) on Iraq which was charged with overseeing the destruction of Iraq's weapons of mass destruction and with establishing an ongoing verification and monitoring regime to ensure Iraq did not acquire such weapons. Vital lessons are drawn here for international security and for the strengthening of the non-proliferation regimes for both biological and chemical weapons.