The present volume deals with benzene, toluene and the xylenes. The widespread, large-scale use of benzene and alkylated benzenes as solvents and chemical intermediates, as well as their ubiquitous presence in the general environment arising from combustion and household products and vehicle fuels, emphasize the need for standard detection techniques in both exposure control and in epidemiological studies. Provision of clear information on efficient and reliable techniques and on the practicability of an overall approach are the aims of this series. Benzene is a human carcinogen, and there are conflicting reports from experimental studies on the carcinogenicity of xylene which have been widely introduced as replacement for benzene. Air, food and water exposure routes are covered in this volume, with emphasis on appropriate sampling techniques that render possible exposure assessment. Included also are very recent advances in biological monitoring via breath analysis, as well as established blood and urine measurements.