In this interview, David Zierler, Oral Historian for AIP, interviews William Eaton, NIH Distinguished Investigator and Chief of the Laboratory of Chemical Physics. Eaton recounts his childhood in Philadelphia and he describes his undergraduate and graduate work at the University of Pennsylvania, where he earned an M.D. a Ph.D. He describes his budding interests in chemical physics during his time in medical school and his formative research at Cambridge, where he worked on protein synthesis. He conveys the serendipity surrounding his decision to join the NIH as a result of his experience with the draft during the Vietnam War. He discusses his offer to head the biophysics program at Harvard, and he explains his decision to remain at NIH. Eaton provides a history of NMR and AIDS research at the NIH, and he describes his research agenda at the NIH, including his seminal work on sickle cell disease and protein folding. At the end of the interview, Eaton reflects on the value of his medical degree over the course of his career.