Recent findings from three separate studies support and extend a large and growing body of early-intervention research literature spanning 30 years. The literature is consistent in demonstrating positive developmental outcomes as a result of intensive early intervention for children of low-income and undereducated families. New analyses confirm that maternal intelligence is a key factor in children's intellectual development, especially when these children are not provided with intensive early intervention. Fortunately, children whose mothers have low IQs respond positively to intensive, high-quality early intervention, which leads to a dramatic reduction in their rates of mental retardation during the intervention program. Unresolved issues include how best routinely to identify children and families who will benefit from such programs, how early to begin programs and for how long to continue them to produce desirable developmental outcomes, and whether sufficient public and political will exists to scale-up early intervention efforts to match the magnitude of the problem in our society.