You cannot hide from radioactivity. Even the book you are holding is slightly radioactive, but there are more serious risks. Radioactivity - the breakdown of unstable atomic nuclei, releasing radiation - is a fundamental process in nature. It is a process that has been harnessed to provide wide and important applications in science, medicine, industry, and energy production. But it remains much misunderstood - and feared, perhaps because nuclear radiation cannot be detected by human senses, and can undoubtedly do great harm if appropriate precautions are not taken. In recent times there have...