Understanding the health literacy of America's adults is important because so many aspects of finding health care and health information, and maintaining health, depend on understanding written information. Many reports have suggested that low health literacy is associated with poor communication between patients and health care providers and with poor health outcomes, including increased hospitalization rates, less frequent screening for diseases such as cancer, and disproportionately high rates of disease and mortality This report describes how health literacy varies across the population and where adults with different levels of health literacy obtain information about health issues. The analyses in this report examine differences related to literacy that are based on self-reported background characteristics among groups in 2003. Analyses presented in this report, including those in appendix E, are intended to provide a summary of the relationship between health literacy and background characteristics of adults, preventive health practices, and sources of health information used by adults. Statistical tables and color enhanced graphic figures are included. Appended are: (1) Sample Health Literacy Assessment Question; (2) Definitions of All Subpopulations and Background Variables Reported; (3) Technical Notes; (4) Standard Errors for Tables and Figures; and (5) Additional Analyses. (Contains 52 tables and 17 figures.)