Over fifteen million children live in families subsisting below the federal poverty level, and there are nearly four million more children living in poverty today than at the turn of the twenty-first century. When compared to their more affluent counterparts, children living in fragile circumstances—including homeless children, children in foster care, and children living in families affected by chronic physical or mental health problems—are more likely to have low academic achievement, to drop out of school, and to have health and behavioral problems. This publication provides a comprehensive analysis of the mechanisms through which socioeconomic, cultural, familial, and community-level factors impact the early and long-term cognitive, neurobiological, socio-emotional, and physical development of children living in poverty. Contributors from various disciplines review basic and applied multidisciplinary research, and propose questions and answers regarding the short- and long-term impact of poverty, contexts, and policies on child-developmental trajectories. In addition, the book features analyses involving diverse children of all ages, particularly those from understudied groups (e.g. Pacific Islanders, Native Americans, immigrants) and those from understudied geographic areas (e.g., the rural United States; international humanitarian settings). Each of the seven sections begins with an overview of basic biological and behavioral research on child development and poverty, followed by applied analyses of contemporary issues that are currently at the heart of public debates on child health and well-being, and concludes with suggestions for policy reform.