Gregory A. Petsko is Professor of Neurology at Weill Cornell Medical College in New York City, and Tauber Professor of Biochemistry and Chemistry, Emeritus, at Brandeis University in Waltham, Massachusetts. He was Professor of Chemistry at MIT from 1978 to1990, when he moved to Brandeis University, where he served as Director of the Rosenstiel Basic Medical Sciences Research Center; he took up his present appointment in New York in April of this year. His awards include the Pfizer Award in Enzyme Chemistry of the American Chemical Society (for his development of methods to visualize reaction intermediates in three dimensions at atomic resolution and in 1991 the Max Planck Prize, which he shared with Professor Roger Goody of Heidelberg for their work on the origins of some human cancers. He is a member of the National Academy of Sciences, the Institute of Medicine, the American Academy of Arts and Sciences, and the American Philosophical Society. He is immediate Past-President of the American Society for Biochemistry and Molecular Biology and is President-Elect of the International Union of Biochemistry and Molecular Biology. His research interests include protein structure and function and the development of methods to treat age-related neurodegenerative diseases, including ALS (Lou Gehrig’s), Alzheimer’s and Parkinson’s Diseases. His public lectures on the aging of the population and its implications for human health have attracted a wide audience on the Internet (his TED talk, for example, has been downloaded over a quarter of a million times). For the past twelve years he has also written a widely-read column on science and society, the first ten years of which have just appeared in book form.