Kam Man Hui, Ph.D., is Associate Professor and Head of the Laboratory of Molecular Immunology, Institute of Molecular and Cell Biology, National University of Singapore. Dr. Hui obtained his B.Sc. and M.Sc. degrees from Washington State University, and his Ph.D. in 1982 from Northwestern University Medical School in Chicago. After postdoctoral research training at the London Hospital Medical College and the National Institute for Medical Research in London, Dr. Hui took up his present appointment in 1987. During his postdoctoral years at the London Hospital Medical College, Dr. Hui was first introduced to research into the human major histocompatibility complex by the late Professor Hilliard Festenstein. Dr. Hui's current research addresses the genetics and regulation of major histocompatibility genes in tumorigenesis. His laboratory is supported by the Singapore National Science and Technology Board. In 1990, jointly with Dr. Bidwell, Dr. Hui first described and patented the application of DNA heteroduplex technology to the HLADR- Dw system, and both colleagues continue to collaborate in the development of this and other related techniques. Dr. Hui has published more than 30 scientific papers and is a member of the American Association of Immunologists. Jeffrey Lewis Bidwell, Ph.D., M.R.C.Path., is Senior Research Fellow and Head of Molecular Research in the Department of Transplantation Sciences, University of Bristol, England. Dr. Bidwell received his undergraduate training in the Pathology Department of the Birmingham Accident Hospital, and in the Microbiology Departments at Ham Green and Southmead Hospitals, Bristol. He obtained his Ph.D. in Molecular Genetics in 1981 at the University of the West of England at Bristol. He was appointed to the United Kingdom Transplant Service in 1983 where he worked until 1992, before becoming a founding member of the academic staff of the newly created Department of Transplantation Sciences at the University of Bristol. Dr. Bidwell is a chartered biologist and is a member of the Institute of Biology and of the British Society for Histocompatibility and Immunogenetics. He is a regular visiting scientist at the Institute of Molecular and Cell Biology, National University of Singapore. He has been the recipient of research grants from the Arthritis and Rheumatism Council and the Leukaemia Research Fund. He has published more than 60 scientific papers. His current interests encompass the molecular genetics of the major histocompatibility complex and in particular, novel genotyping techniques.