In an intriguing series of experiments carried out many years ago, a common scientific belief, feted by no less than three Nobel prizes, was brought into question. The observations were about proteins—the molecules that the genetic code specifies and that are in one way or another central to all of life’s activities. The experiments however were not about what proteins do, but how they are moved, in particular how they are moved from where they are made to where they act. The results of these studies conflicted with the standard view of how this happens, and thus became controversial.