This is the final volume in a three-volume work that has addressed the scientific methodologies relevant to clinical neurobehavioral toxicology. Volume III attends to what is known about industrial and environmental chemicals, medicines, and substances of abuse and how these agents affect the central nervous system. How to determine that a specified substance has caused harm is emphasized by way of case examples and discussion. Illnesses and behavioral variations that compete with toxicant-induced explanations for findings in a given case, as well as the various controversies that can arise around issues of diagnosis and causal determination, are treated comprehensively in this volume.