Thomas H. Shawker, M.D. , is chief of the ultrasound section in the Imaging Sciences Program at the National Institutes of Health, a professor of radiology at the United Services University, and a fellow of the American College of Radiology. He is chairman of the National Genealogical Society's Family Health and Heredity Committee and president of the Prince George's County Genealogical Society. He is the author or coauthor of over two hundred scientific publications and a speaker on both medical and genealogical topics. He and his wife live in Maryland.William J. Miller is the author of Mapping for Stonewall: The Civil War Service of Jed Hotchkiss , winner of the Fletcher Pratt Award for best nonfiction Civil War book of the year, and considered the best study of the most famous mapmaker of the Civil War. A former editor of Civil War Magazine, Miller has written or edited seven books and published more than 100 articles on the conflict. A strong advocate of battlefield preservation, Miller leads map-based tours of Virginia's battlefields at every opportunity.