Concentrations of pollutants in the atmosphere have increased dramatically over the last century and many of these changes are attributable to anthropogenic activities. The influence of acid rain has been well studied, but there has been no extensive exploration of other pollutants, such as toxic chemicals, heavy metals and radionuclides. Natural ecosystems, especially forests, tend to accumulate many of these pollutants which subsequently can affect ecosystem health. These contaminants may be very damaging to the environment in Eastern Europe, where the rapid disappearance of forest is the result not only of contamination but also of poor forest management practices. The current book is designed to reduce the uncertainty in our current knowledge of forest radioecology. The three topics it embraces are (a) Modelling, (b) Measurements and Data, and (c) Countermeasures and Risk Assessment.