The detrimental effects of lead exposure in children have been known for over 100 years. Although a few initial measures implemented about 30 years ago were effective in somewhat reducing levels of lead exposure in children, relatively little has been done recently from a policy perspective to protect children from lead. We now know from recent research that much more work is needed. Recent events highlighted in the media show that several urban communities still have unacceptable levels of lead in water systems. Early research identified high levels of lead as being particularly detrimental to children's intellectual and behavioral development. New studies have discovered that lower levels of lead, levels once thought safe, also cause considerable damage to children's developmental outcomes. This social policy report summarizes new data on the intellectual, academic, and behavioral deficits seen in children exposed to both low and high levels of lead. It discusses the biological and neurological mechanisms of lead poisoning, explores sources of environmental lead exposure and lead abatement practices, and shows that current federal and state-level child screening and lead level reporting practices are inadequate. The report also makes policy recommendations centered on increasing education, intensifying abatement efforts, strengthening and regulating mandatory screening practices, and reducing the federal threshold of allowable levels of lead. (Contains 1 figure.) [Commentaries from Joel Nigg, Elise Gould, Alexander Hertel-Fernandez, and Bruce Lanphear are included. Commentaries are individually referenced.]