This book provides a warning to the United States about the imminent danger of a terrorist attack using radioactive materials. Such materials are ubiquitous in our society and can be obtained from over 25,000 sources in the USA. In this unsymmetrical war with terrorism, the beneficial and life-saving advantages of radioactive materials can be turned against us. This book is intended to inform the reader of the dangers of terrorist attacks, to show how attacks can be mounted and, more importantly, to indicate how the consequences of an attack can be mitigated. Terrorists use fear as a weapon; this book shows how an informed public can overcome our natural aversion to all things radioactive and fight back against the potentially paralyzing effects of such an attack.