The proliferation of chemical, biological, and nuclear weapons is now the single most serious security concern for governments around the world. Peter R. Lavoy, Scott D. Sagan, and James J. Wirtz compare how military threats, strategic cultures, and organizations shape the way leaders intend to employ these armaments. They reveal the many frightening ways that emerging military powers and terrorist groups are planning the unthinkable by preparing to use chemical, biological, or nuclear weapons in future conflicts. Distinguished specialists consider several states and organizations that have this weaponry: Iraq, Iran, India, Pakistan, North Korea, and Israel, as well as the Aum Shinrikyo cult. The contributors expose plans for using unconventional weapons, highlighting the revolutionary effects these arsenals might have on international politics and regional disputes.