An attempt to describe the meaning and origin of radiation, the difference between natural radiation from outer space and the earth around us and man-made radiation. It also provides an action guide to sensible judgements over what to do following an accident and radiation release. The big reactors, their sites and potential weaknesses are discussed as well as safety levels in the food we eat. Peter Bunyard is author of Nuclear Britain, The Politics of Self Sufficiency and The Green Alternative Guide to Good Living.