For the past few years, books on nuclear war have been proliferating as fast as atomic particles in a fission reaction. If astronomer Carl Sagan is the ""Dr. McCoy"" of this new subgenre--emotional, sometimes brash, always eloquent, like the character familiar to ""Star Trek"" fans--then Dotto is the phlegmatic, utterly rational ""Mr. Speck."" Three years ago, scientists from more than 30 countries were recruited to cull data from state-of-the-art computer models and reach a consensus on the physical and biological effects of a nuclear conflict. Journalist Dotto compressed into one slim volume the two resulting technical tomes commissioned by the Scientific Committee on Problems of the Environment (SCOPE) of the International Council of Scientific Unions (ICSU) and published last year. Assuming that only one-half to one-fifth or less of the world's nuclear arsenal was detonated, SCOPE came up with the same dreadful predictions of a ""nuclear winter"" as other researchers, or ""acute climatic disturbance,"" in its calculatingly passionless prose. This precipitous drop in temperature, lasting weeks or months, would be caused by massive, sooty plumes rising from hundreds of major urban fires and blocking at least 90% of the sunlight that normally falls on the Northern Hemisphere (which would bear the brunt of the bombing). Agricultural productivity worldwide would collapse as temperatures plummeted, rainfall patterns were disrupted, food stockpiles depleted, and distribution systems destroyed. According to SCOPE, mass starvation would cause more deaths than the radiation, fires and the blasts themselves. This book was designed for those looking for matter-of-fact descriptions of Armageddon. As advertised, the writing is relatively ""nontechnical,"" ""balanced"" and ""nonalarmist."" It is also graceless and eerily detached.