We begin this review in Chapter II by addressing the question, How many children are uninsured? We present key estimates of the uninsured using the most recent data available. We compare and contrast the estimates and discuss methodological issues involved in using survey data to make the estimates. In Chapter III, we present the characteristics of uninsured children as described in the literature. In Chapter IV, we analyze the literature on the question, How many uninsured children are eligible for Medicaid and what is the Medicaid participation rate for children? In this chapter we also describe the various ways that researchers have used survey data to estimate eligibility for the Medicaid program. As a point of comparison for Medicaid participation rates, we present literature on the participation rates for the AFDC and Food Stamp programs. In Chapter V, we analyze the literature on the characteristics of uninsured children who are eligible for Medicaid. In Chapter VI, we summarize our findings and discuss the next steps in this project.