Clarence E. Walker, Professor of History at the University of California, Davis, is the author of Mongrel Nation: The America Begotten by Thomas Jefferson and Sally Hemings (Virginia) and We Can't Go Home Again: An Argument about Afrocentrism. Gregory D. Smithers, author of Science, Sexuality, and Race in the United States and Australia, 1780s-1890s, is Lecturer in American History at King's College, University of Aberdeen, in Scotland.