The clearest approach yet- for the layman- to the problems created and solved by the tremendous advancement of science during the past 50 years in the conduct of war. The author was a leading scientist during World War II, and here summarizes the latest developments in all media,- air, sea, land, undersea, in terms easy for any reader to understand and fascinating for many. He does not deal in technical terms, mathematical formulae, scientific terminology, but he writes of radar, proximity fuses, explosives, jet propulsion, submarine and anti-submarine warfare, chemical and biological warfare, and so on. His intellectual comparison of dictatorship vs. democracy, his reasons why an anti-democratic system cannot explore science to the full, his suggestions for education and planning make challenging reading. Not limited to the usual audience for such data.