Paul Brown recently retired as a senior investigator in the Laboratory of Central Nervous System Studies at the National Institutes of Health. He is a board-certified internist and—by virtue of having devoted more than 40 years of his career to the study of transmissible spongiform encephalopathy—an apprentice neuroscientist and the author of more than 350 publications. His most recent research focuses on iatrogenic Creutzfeldt-Jakob disease, the potential for disease transmission through the administration of blood and technologies to inactivate prions in contaminated meats. He has served as chairman of the TSE advisory committee to the Food and Drug Administration and presently serves as a consultant to the European Community CJD surveillance program. His qualifications to write about spongiform encephalopathies include a long history of handling infected tissues, an increasing degree of forgetfulness, diminishing visual acuity and an occasional nocturnal muscle twitch. Address: 7815 Exeter Road, Bethesda, MD 20814 Internet: paulwbrown@comcast.net