Governments and the nuclear power industry have a strong interest in playing down the harmful effects of radiation from atomic weapons and nuclear power plants. Over the years, some scientists have supported the view that low levels of radiation are not harmful, while other scientists have held that all radiation is harmful. The author examines the radiation effects of nuclear bombs dropped on Japan in 1945; nuclear weapons testing; plutonium plant accidents at Windscale in England and Chelyabinsk in the Soviet Union; nuclear power plant emissions during normal operations; and the power plant accidents at Three Mile Island in the United States, Chernobyl in the Soviet Union, and Fukushima Daiichi in Japan. In each case, he finds a pattern of minimizing the damage to humans and attributing evidence of shortened life spans mostly to stress and social dislocation rather than to radiation. While low-level radiation is now generally accepted as harmful, its effects are deemed to be so small that they cannot be distinguished from the much greater effects of stress and social dislocation. Thus, some scientists declare that there is no point in even studying the populations exposed to the radioactive elements released into the atmosphere during the 2011 accident at Fukushima.