Biomonitoring is the measurement of a chemical, its metabolite, or reaction product in biological matrices, most commonly urine and blood products. Biomonitoring studies of environmental stressors are used to characterize exposures, estimate internal dose levels, and evaluate potential for human health impacts. This collection provides data on human exposures through analysis of biological samples. It also includes description of novel methodologies to use biomonitoring for determining exposures and related health effects.