This monograph focuses on the literacy performance of U.S. adults in comparison to adults in other high-income countries, underscoring the fact that the overall U.S. performance is mediocre at best and that the U.S. is a world leader in the degree of inequality between the best and poorest performers. The monograph describes the National and the International Adult Literacy Surveys, explaining three literacy measures (prose, document, and quantitative) that are used to characterize adults' literacy proficiencies. The monograph's six sections examine "The National and International Adult Literacy Surveys"; "Comparing U.S. Literacy Proficiency with That of All High-Income Countries"; "The Literacy Proficiency of Key Demographic Subgroups in the U.S." (by gender, age, educational attainment, race/ethnicity, and native born versus foreign born status); "Inequality of Literacy Skills among U.S. Adults"; "The Future Outlook for Inequality among U.S. Adults"; and "Summary of Findings and Policy Recommendations. Four tables are appended. (SM)