This book arises out of a workshop on lead exposure and child development which was held at the University of Edinburgh on 8th-12th September 1986. It was organized jointly by the Commission of the European Communities (CEC) and the US Environmental Protection Agency (EPA), in association with the UK Department of the Environment and the Scottish Home and Health Department. It brought together most of the internationally recognized groups working on the effects of lead exposure on child development including child psychologists, psychiatrists, neurologists, epidemiologists, toxicologists, stati sticians, and medical practitioners. One of the unique features of the meeting was that it included workers from initially separate fields of lead research, in particular those undertaking studies in infants and in older children, and those carrying out behavioural research in animals, as well as those undertaking biochemical studies on mechanisms of lead effect. The structure of this book reflects the main elements of the meeting. As such it includes three main sections. The first consists of two major state-of the-art reviews, and two invited introductory papers. The reviews were prepared for the organizers of the conference by two of the Editors. The objectives were to assess critically the state of current knowledge in this field and to provide a scientific basis both for policy decisions and for further research. The review prepared by Marjorie Smith for the Commission of the European Communities focusses on methodological and design issues, and summarizes our present scientific knowledge in this area.