After three decades of research, neurobehavioral toxicity is now acknowledged as a significant outcome of chemical exposure. Its health and economic costs may exceed those by cancer by substantial amounts. This new perspective has been accompanied by efforts designed to explore the responsible mechanisms, to design applicable risk assessment procedures, and to determine the consequent policy implications. This publication includes 25 papers from international experts and includes: human neurobehavioral toxicity; animal behavioral methods; selected model compounds; and risk assessment.