This important book provides the most informative and judicious analysis to date of one of the most critical strategic nuclear questions of the next two decades. Can ballistic missile defense be made to work and, if so, is it desirable, given that it could overturn accepted notions of mutual deterrence? There remains no clear answer and the authors provide a range of opinions. On the technical issue: research and development progress has been made since the great ABM debate of a decade ago, and it will continue, but the ABM Treaty would have to be abrogated or revised, and the degree of confidence in ballistic missile defenses is unlikely to allow the superpowers to move away completely from their mutual hostage relationship. Politically, ballistic missile defense would create enormous difficulties for America's allies and in East-West relations. Yet there are counter-arguments, and all points of view are responsibly spelled out in this thorough study. One noteworthy observation is that the implementation of missile defense forces and strategy would be a very long-term process at best.