Everyone agrees that we can’t change the past. But what about the future? Though the thought that we can change the future is familiar from popular discourse, it enjoys virtually no support from philosophers, contemporary or otherwise. In this paper, I argue that the thesis that the future is mutable has far more going for it than anyone has yet realized. The view, I hope to show, gains support from the nature of prevention, can provide a new way of responding to arguments for fatalism, can account for the utility of total knowledge of the future, and can help in providing an account of the (notoriously vexed) semantics of the English progressive. On the view in question, the future is mutable in a quite radical sense: perhaps, at one time, it was true that Obama would never be president. And then the future changed. And he became president.