A collection of essays put together by the Union of Concerned Scientists, exploring the potentials for danger in President Reagan's Strategic Defense Intiative. The same group which in 1984 put out The Fallacy of Star Wars this time addresses in greater detail specific technical aspects of Star Wars' technology. The volume takes as its starting point the recognition that though Reagan launched his dream with an idealistic purity of creating a foolproof shield from incoming nuclear missiles, researchers and lower-level policy-makers have actually bastardized the program, opting for a limited defense system in which the protection of military targets, not population centers, is their main concern. The essays here cover a wide range of SDI-related issues, ranging from the political aspects to command and control problems to the Soviet response (the main crux of the criticism of Star Wars being its destabilizing influence on the arms race) to Europe's stance in Star Wars' shadow. By far the most compelling chapter covers the difficulties of creating the requisite software to control such a pie-in-the-sky system. The authors of this essay state that current state-of-the-art renders that possiblity nil and makes SDI a desperately dangerous game that, with the wrong or hastily applied software, could backfire. (The tone of this volume, alas, does not admit of any possibilities that research might overcome this bug.) There is no doubt about the stance of this group of essayists, which renders the volume unrelievedly negative. But at least they aren't just preaching to the converted, and an honest difference of opinion might lead to ultimate improvements or refinements of the concept.