1 Nancy Breen and Xinzhi Zhang are with the National Institute on Minority Health and Health Disparities (NIMHD), National Institutes of Health (NIH), Bethesda, MD. James S. Jackson is with the Institute for Social Research, University of Michigan, Ann Arbor. Fred Wood is with the National Library of Medicine, Bethesda, MD. David W. S. Wong is with the Department of Geography and Geoinformation Science, George Mason University, Fairfax, VA. Nancy Breen is also a Guest Editor for this supplement issue.