This guide was originally created out of the necessity to provide practical assistance to a wide readership quickly after Chernobyl. Since then, it has been extensively expanded and updated, most recently after Fukushima, which brought the topic back into public awareness. It answers questions such as: What is the nature of radioactivity? Why is radioactivity so dangerous to our health? How can we protect ourselves from these dangers? What significant contribution does homeopathy provide in protecting against damage from radioactivity? The drug evaluations by the two experienced homeopaths and authors regarding X-rays and plutonium are also highly interesting. The guide is particularly helpful for individuals undergoing imaging procedures such as computed tomography and radiation therapy (for example, in cancer treatment).