As soon as he finished his degree, he changed course, heading straight for postdoctoral studies in a different field at the University of California, Berkeley. There he extracted a promise from his prospective adviser--noted biochemist Peter G. Schultz--that he would be able to say good-bye to physical chemistry and immerse himself entirely in immunology. Although Romesberg harbors no regrets about his initial decision to study something rudimentary and dull, he remarks that going directly into biology would probably have been a mistake. The complexity of the field ensures that all too many graduate projects end up with only desultory results. "At Cornell, I was fortunately able to work on a small system that was amenable to a complete description. It was something that was actually solvable and allowed me to worry about fundamental questions," he concedes. "I always have this tendency to reduce things to basic molecular-, chemical-level questions, and I think that has served me very well."