This book provides an overview on the molecular mode of action of carcinogenic polycyclic aromatic hydrocarbons (PAHs). PAHs are by-products arising from incomplete combustion of organic matter that are frequently released into our environment, and thus are ubiquitously detectable. Many PAHs are strong carcinogens in rodent bioassays and have been linked to increased incidences of various types of cancer in humans. The present book covers all aspects of PAH-induced carcinogenesis; it is a collection of articles written by some of the most recognizable PAH researchers, reviewing the present knowledge in this field. The topics include: exposure to and biomonitoring of PAHs in the human population; metabolic activation of PAHs; genotoxicity and repair of PAH-induced DNA damage; and factors modulating individual susceptibility to the deleterious effects of PAHs.