Martin McGuire has written for the specialist and the concerned layman a highly original and valuable contribution to our understanding of the arms race, based upon economic theory in general and the theory of economic duopoly in particular. He calls attention to the fact that when two world powers face each other with massive allocations of resources for arms, and when each regards the other as the major, if not the sole, threat to its own security, the question of accurate information about the strength and intentions of the adversary arises for each side in many and various ways. As a result, this study is a pioneering, analytic effort to approach the value of keeping secrets from or of obtaining information about an enemy. The author is concerned with such questions as: what is the loss in being only 50 percent confident rather than certain that the adversary doesn't have more X missiles or missiles of yield W megatons or of accuracy C thousand feet? Should one insist on being 95 percent sure when bargaining for arms control? How can a side compensate for its uncertainty most efficiently? An understanding of these problems can not only increase our security; it may help as well to contain or control the entire two-sided race.