Missile X is a nuclear weapon of unprecedented destructive power. Once deployed, it could destroy all Soviet land missiles in one thiry-minute barrage. If based on land, it will require a construction effort greater than the Panama Canal or the Great Wall of China.

But the superweapon is also vulnerable to attack, and its construction has enormous economic and political consequences. Thus, since its inception in 1970, MX has been fiercely debated in the White House, the Pentagon, and on Capitol Hill. President Jimmy Carter called it, initially, "the craziest thing I ever heard," and yet only two years later, caught up in the implacable logic of the nuclear arms race, he would approve an expanded budget for its development.

John Edwards has interviewed all the major actors in this drama, and through his incisive portraits of the scientists, politicians and generals who control the weapons community, he shows how policy grows out of their personal and ideological conflicts.