Gary Felsenfeld is an NIH Distinguished Investigator in the National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda. He obtained his Ph.D. in physical chemistry at the California Institute of Technology and carried out postdoctoral work at the Mathematical Institute, Oxford. He has spent most of his career at NIH. Research in Dr. Felsenfeld’s laboratory has focused on the chemistry of interactions between DNA and regulatory proteins, and especially on the relationship between chromatin structure and gene expression. In recent years he has been particularly interested in the function of insulator elements, and the identification of factors that stabilize long range interactions in the nucleus. He is a member of the National Academy of Sciences since 1976.