Experts argue that there are still significant technical and logistical barriers that discourage terrorists from developing weapons of mass destruction.
The authors evaluate the risks from several popular doomsday scenarios including smallpox biological terrorism, grey goo, and nuclear terrorism.
Against the backdrop of the war on terrorism, an expanding group of government researchers is at work on a nationwide sensor network that someday could provide a real-time early-warning system for a wide array of chemical, biological and nuclear threats across the United States.