A year ago the President of Harvard suggested to six faculty members, all with considerable defense and arms control expertise, that they write a book for the general reader laying out the facts as well as the dilemmas of the nuclear age. This has been done, remarkably well. (It must have helped that the six faculty members have compatible views, none reflecting either the Committee on the Present Danger or the freeze movement.) Much accurate information, and a considerable number of judgments, are imparted in a lively text. An excellent primer that should be intelligible to concerned citizens from high school students on upwards.