During the last two decades, the infrastructure of the U.S. economy has undergone a fundamental set of changes. It has steadily increased its reliance on its service sector and high-technology economy. The U.S. has come to depend upon computers, electronic data storage and transfers, and highly integrated communications networks. The result is the rapid development of a new form of critical infrastructure--and one that is exceedingly vulnerable to a new family of threats, loosely grouped together as information warfare. This detailed volume examines these threats and the evolving U.S. policy response.