Part B has been instituted to provide a quarterly outlet for in-depth critical reviews, both commissioned and unsolicited, which complement the original research published in the Journal of Toxicology and Environmental Health . In keeping with the original scope, Part B will focus on environmental toxicology in general as well as on special interest fields such as: target organ toxicities; immunotoxicology; risk assessment; carcinogenesis and mutagenesis; ecotoxicology and aquatic toxicology; environmental factors affecting health. Emphasis will be on the toxicological effects of natural and anthropogenic environmental pollutants and their action on both intact organisms and in vitro systems. Part B: Critical Reviews serves as an indispensable resource for toxicologists, environmentalists, pharmacologists, biochemists, radiation biologists, and epidemiologists, as well as for health care professionals, health and safety administrators, environmental and occupational physicians, oncologists, and hazardous substance professionals.