Book excerpt: The USDA's Economic Research Service previously identified over 6,500 food desert tracts in the United States based on the 2000 Census and 2006 data on locations of supermarkets, super-centres, and large grocery stores. This book examines the socio-economic and demographic characteristics of these tracts to see how they differ from other census tracts and the extent to which these differences influence food desert status. Relative to all other census tracts, food desert tracts tend to have smaller populations, higher rates of abandoned or vacant homes, and residents who have lower levels of education, lower incomes, and higher unemployment. Efforts to encourage Americans to improve their diets and to eat more nutritious foods presume that a wide variety of these foods are accessible to everyone. But for some Americans and in some communities, access to healthy foods may be limited.