JOHN F. SCAMEHORN is Associate Professor of Chemical Engineering and Associate Director of the Institute for Applied Surfactant Research at the University of Oklahoma in Norman. He also serves as Vice President of Surfactant Associates, Inc., a company specializing in surfactant applications in Norman, Oklahoma. Dr. Scam horn is the editor of the book Phenomena in Mixed Surfactant Systems, associate editor of the Journal of the American Oil Chemists' Society. and an editorial board member of the journal Colloids and Surfaces. Among the professional societies he belongs to are the American Chemical Society, American Institute of Chemical Engineers, American Oil Chemists' Society. Society of Petroleum Engineers, and American Electroplaters and Surface Finishers Society. Dr. Scam horn received the B.S.Ch.E. (1973) and M.S. (1974) degrees in chemical engineering from the University of Nebraska at Lincoln, and Ph.D. (1980) degree, also in chemical engineering, from the University of Texas at Austin. JEFFREY H. HARWELL. is Associate Professor of Chemical Engineering at the University of Oklahoma in Norman as well as President of Surfactant Associates, Inc. in Norman, Oklahoma. The author or coauthor of some 27 journal articles, book chapters, and proceedings papers on surfactants, Dr. Harwell serves as Program Manager for the Separations Program of the Engineering Directorate of the National Science Foundation (1988-89). He is a member of the American Chemical Society, American Institute of Chemical Engineers, and Society of Petroleum Engineers. Dr. Harwell received the B.A. (1974) degree in chemistry and M.S. (1979) degree in chemical engineering from Texas A&M University in College Station, and Ph.D. (1983) degree in chemical engineering from the University of Texas at Austin.