Dr. Bruno Kolb is an internationally recognized expert on gas chromatography. He joined Perkin--Elmer in Germany in 1962, where he worked on GC applications and on instrument development with special emphasis on specific detectors. Until his retirement in 1996 he managed the GC--applications laboratory within the marketing group. He has been a guest lecturer for 10 years at the University of Konstanz, as well as at many international meetings, and has published many journal articles, book chapters, and books. Dr. Leslie S. Ettre was associated with the Perkin--Elmer Corporation for over 30 years before retiring in 1990 as a senior scientist. From 1988 to 1994 he served as an adjunct professor at the Department of Chemical Engineering of Yale University, and remains associated with the Department as a Research Affiliate. He has lectured widely in many countries of the world, published over 200 scientific and technical papers, and has served as the author and editor of numerous books, including the Encyclopedia of Industrial Chemical Analysis. Dr. Ettre's many awards include the National Award in Chromatography of the ACS, and the AJP Martin Award of the Chromatography Society, the highest honors in the United States and Europe, respectively.