Biological markers used to assess the effects of environmental pollution have attracted considerable attention from regulatory agencies and are currently under evaluation at a number of research facilities throughout the world. However promising a biomarker-based biomonitoring approach may be, the development of this concept is complicated by a range of technical issues. This book provides a conceptional framework for research and application of biomarkers. International experts on biomonitoring have formulated a unified strategy for the development and validation of biomarkers in assessing environmental health as well as appropriate prools for their implementation and interpretation in a biological monitoring program.