This manual is concerned with accidents or emergencies which involve sources of ionizing radiation. It does not cover other forms of radiation such as non-ionizing radiation (ultra-violet, light, radiofrequency radiations), heat, etc. Most radiation accidents have involved individuals either at the workplace or with medical misadministrations; they have received external exposure from X-ray or gamma-ray sources or have been contaminated with radioactive material. A few members of the public have also been involved through misadventures with radioactive sources although these may not be thought of as accidents; more commonly, they are referred to as `incidents`. For the purpose of this manual, there is not differentiation between an accident and an incident, as the medical care required is the same in both situations. Some of the reference papers are reprinted at the back of the manual. 17 refs., 12 tabs., 9 figs.