Translators and quality controllers generally acquire knowledge of how to revise their own or others' work by trial-and-error, by working under an experienced reviser, or by attending workshops. There are also one or two publications and in-house manuals that purvey advice for successful revising. Recently, however, Translation Studies scholars have begun to conduct empirical studies in which they observe the revision process through methods such as recording and playing back keystrokes, asking translators to think aloud into a microphone as they revise their own work, or comparing different revised versions of a given draft translation. This article reviews a selection of studies of revision in English, and concludes with some suggestions about questions that need attention.