This volume in the IARC manual series presents isomer-specific methods of analysis of PCDDs and PCDFs in air, in drinking and wastewater, in food, and in biological matrices, with emphasis on appropriate sampling techniques that render possible exposure assessment. Included are also methods for biological monitoring via milk, blood, and adipose tissue measurements. Such data will be crucial for the comparison and pooling of results from the different epidemiological studies that are necessary to resolve and quantify the carcinogenic risk arising from these compounds.