This report presents an overview of research on childhood lead exposure and poisoning, and the related social issues. The report first summarizes the history of lead poisoning and its prevalence in the United States, and discusses the basis for recent changes in guidelines for lead exposure by the Centers for Disease Control (CDC). The report then reviews the animal and human research literature on lead exposure and poisoning, focusing on the neurobehavioral effects of lead poisoning, methodological issues, and directions for future research. It then discusses the public policy implications of lead exposure and the financial costs of abatements, finding that the removal of lead from children's environments has proven to be more expensive, complicated, and time-consuming than once thought. The report concludes that while the effects of high levels of lead exposure have been documented for nearly a century, the specific effects of lower levels of lead (10 to 15 micrograms per deciliter of blood) are less clear, although the data seem to support that even low-level lead exposure causes cognitive and behavioral deficits. (Contains 68 references.) (MDM)