Frank R. Parker is Director of the Voting Rights Project of the Lawyers' Committee for Civil Rights Under Law in Washington, D.C. He was a civil rights lawyer in Mississippi from 1968 to 1981.Henry Pickering Walker (1911-1984), a well-known historian of the American West, was the author of The Wagonmasters: High Plains Freighting from the Earliest Days of the Santa Fe Trail to 1880 and coauthor of Historical Atlas of Arizona, also published by the University of Oklahoma Press.