Human health, aquatic, and terrestrial ecosystems are all under threat from increasing levels of environmental radiation from a variety of sources, many of them anthropogenic. This book surveys the current state-of-our-knowledge of the fundamental processes that result from the interaction of environmental (both ionizing and UV) with living matter. Current concepts of risk estimation and radiation protection are also considered. The book covers the consequences of radioactive pollution from accidents to nuclear power plant, especially in large areas of the former Soviet Union; the global problem of an increase in the incidence of UVB radiation at the earth's surface due to the depletion of the stratospheric ozone layer; the increase of natural radiation levels in areas of former uranium mining; and the increased levels of natural radiation experienced in air travel and space flight.