A detailed history of the Missile Defense Agency, a little-known task force created to intercept nuclear missiles. Wasserbly, editor of Jane's International Defence Review, focuses on the personnel at Fort Greely in northern Alaska, the main launch site for the interceptors, chosen because its location allows a clean shot at ICBMs coming over the Pacific or the North Pole. The base, closed down in 1999, reopened in 2001 when President George W. Bush decided to withdraw from the Anti-Ballistic Missile Treaty. Reconstruction took another two years while crews trained to operate the sophisticated equipment. The base was initially manned by full-time National Guard troops. At the same time, at Schreiver Air Force Base in Colorado, a command center tracks incoming missiles and passes information and orders to the teams at Greely. The book follows a couple dozen people, from agency directors to crew members and military police charged with keeping intruders out of the base. As you might expect in Alaska, the latter are more often moose and bears than human. The author deals with such issues as changing the length of shifts, but there are also colorful stories of daily life at Greely--and some humor. Wasserbly attempts, without much success, to generate narrative tension as the crews work to test their equipment, especially in live tests against incoming missiles. At first, the tests were jinxed by technical problems, and the Pentagon responded by cutting funds. Eventually, the glitches were fixed, and the crews are confident of success--though there's really no way to simulate an actual attack. Without a suspenseful conclusion, the book is ultimately anticlimactic. For die-hard military buffs who want a look at the people who operate an important element of America's anti-missile defense. (8-page color photo insert) Copyright (c) Kirkus Reviews, used with permission.