Part 1 Introduction to risks: the risks of modern life in Britain; risks of cancer and mutation - the background; radiation and cancer. Part 2 Power production, conservation and needs: energy supplies - "renewable" resources; energy supplies - coal, oil, gas and nuclear; conservation of energy. Part 3 Quantitative discussion of risk: accidental risks to the public due to energy production other than nuclear; risks of nuclear accidents; the numbers killed in routine power production; wastes from the nuclear power industry; wastes from other power sources. Part 4 Environmental effects, the opposition of nuclear power, conclusion: terrrorism and proliferation; the environmental effects of power production; the oppposition to large-scale power production. Appendices: a mechanism of cancer initiation; some properties of radioactive nuclides; the nuclear physics of reactors.