P. M. S. Blackett, Nobel Laureate in Physics for 1948, is a scientist of distinction and outstanding ability. He is therefore capable, as all good scientists should be, of careful and objective reasoning concerning matters that do not impinge too closely upon his faiths and implicit beliefs. Unfortunately, the subject matter of his book, Fear, War, and the Bomb, suggests that Blackett has allowed his pronounced political sympathies to warp his observations and his reasoning. They have apparently led him to suppress large numbers of pertinent facts, to ignore many crucial technical and political possibilities, and to depreciate the honesty and good faith of his government and of ours to an absurd degree.