This volume was inspired by an annual meeting of the American Col lege of N europsychopharmacology held in Maui, Hawaii. A panel on psychobiological issues of childhood was held, with presentations devoted to antidepressant drug levels in depressed prepubertal children, re sponses of normal and hyperactive children to stimulant medication, and the vulnerability of the adolescent offspring of manic-depressive parents to affective illnesses. The session drew a large crowd, and it seemed appropriate to develop these topics in a book. Many of the authors in this volume attended that conference, and the book reflects the fact that psychobiological research in children has moved even further along than was envisioned at Maui. In keeping with developments in the field, this volume surveys key topics of interest, including nosological issues surrounding the attention deficit disorder of childhood, the ontology of neurotransmitter systems in the human brain, and the relation between child psychiatric disorders and sleep patterns. Other studies link the clinical effects of drugs with plasma DBH activity or with attentional measures. The side effects of on growth are examined, as well as the ethical issues involved in drugs on children. These areas continue to be of vital interest.