More than 10 million children from birth through age six in the US live in low-income families. Although large investments in early childhood intervention programs are evident, is the field fully exploiting its potential to address the diverse needs of children and families? One means of addressing this question is to focus on the efficacy of home-visiting as a service delivery strategy. In the US, it is estimated that the field of home visitation serves between 400,000 and 500,000 children and their families across 40 states. Because of its visibility, the field of home visitation is the target of strong debate and scrutiny. With its roots in European countries, home visitation as a service delivery model came to the US in the late 19th century. Today, opinion is divided on the effectiveness of home visitation due to the perplexing nature of the empirical literature. For example, depending on which studies are reviewed, different conclusions can be drawn about the effectiveness of home visitation programs. Nevertheless, policymakers have proposed federal legislation which would provide a direct funding streamline for home visitation services--the most recent being President Obama's commitment of 750 million dollars over 5 years. The purpose of this report is to present the major concerns and current developments in the field of home visitation. We review US studies of large, established home visitation program models which have been broadly evaluated and point to areas ripe for future research (e.g., home visitation and immigrant communities, the role of implementation fidelity). Overall, stakeholders should invest in programs which are committed to continuous quality improvement as well as rigorous evaluations of efficacy, utilizing diversified methods to assess the complexity of programs nested within their communities. Although challenges exist in the execution of a System of Care approach to early childhood prevention and intervention services, home visitation will play an important role in a network of social supports which can address different developmental stages and outcomes for young children and their families. (Contains 1 footnote, 1 figure, and 1 table.) [Commentaries by Ron Haskins, Christina Paxson, Jeanne Brooks-Gunn, Deborah Daro, Barbara Hanna Wasik and Donna Bryant are included.]