Because the brain is the organ from which all cognition and emotion originates, healthy human brain development represents the foundation of our civilization. Accordingly, there is perhaps nothing more important that a society must do than foster and protect the brain development of our children. Building on a well-established body of behavioral data and a smaller but expanding body of neuroimaging data, Hair et al1 provide even more powerful evidence of the tangible detrimental effects of growing up in poverty on brain development and related academic outcomes in childhood. Using data from the National Institutes of Health Magnetic Resonance Imaging Study of Normal Brain Development, the investigators demonstrated that children living 1.5 times below the federal poverty level had smaller volumes of several brain regions critical for cognitive and academic performance (gray matter, frontal and temporal lobes, and the hippocampus). While smaller brain volumes in children reared in poverty have been previously demonstrated in several investigations2,3 and poor academic and cognitive outcomes of children living in poverty have been well known for several decades,4 Hair et al1 went further to elucidate the mechanism of this relationship. The findings of the Hair et al study1 showed that poor cognitive and academic performance among children living in poverty was mediated by a smaller hippocampus and frontal and temporal lobes and that the decrease in volume of the latter 2 structures explained as much as 15% to 20% of the achievement deficits found. Given the nature of the study sample investigated, where children facing numerous other risk factors for poor brain development were screened out, it is likely that the effects reported represent an underestimate of the magnitude of risk in the general population.