This comprehensive overview of local food systems explores alternative definitions of local food, estimates market size and reach, describes the characteristics of local consumers and producers, and examines early indications of the economic and health impacts of local food systems.  Statistics suggest that local food markets account for a small but growing share of U.S. agricultural production.  For smaller farms, direct marketing to consumers accounts for a higher percentage of their sales than for larger farms.  Findings are mixed on the impact of local food systems on local economic development and better nutrition levels among consumers, and sparse literature is so far inconclusive about whether localization reduces energy use or greenhouse gas emissions.