A gathering and updating of the scientific research on the global winter that would very likely follow a nuclear war. A large-scale nuclear war might kill perhaps a third of the world's population; the nuclear winter that followed might kill the other two-thirds. Only in 1982 did scientists discover what a large nuclear exchange could do to the world's atmosphere and climate. Dust, smoke and soot from the explosions and vast fires would blot out the sun for months, bringing a dark and severe winter to the northern hemisphere even in July. Vegetation would die, animals that depend on the vegetation would die and humans that depend on both would die. Those experiencing the frozen earth might well conclude that the first dead were the luckier. Some in the scientific community regard the facts about the nuclear winter to be the most significant discovery of this century. We now know that for the first time in history, there is a real possibility that human life on the planet could be extinguished. The scientists first shared their knowledge with the public in a major conference in Washington in 1983 attended by 500 scientists, including some Russians. The authors, two physical scientists and a biologist, all British, present their nightmare scenario in a calm tone, carefully weighing the evidence for and the uncertainties about their thesis. The book is intended for a lay audience, the writing clear and simple. The authors have segregated the scientific data and equations apart from the main narrative. An important work that enlarges our still too-small store of knowledge about the almost unimaginable catastrophe that very likely would overwhelm us after a nuclear war.