Although Samuel Johnson considered footnotes ‘necessary evils' and warned that the mind would be ‘refrigerated by interruption', annotation has always been key in bridging the historical and cultural divide separating Shakespeare's late-sixteenth or early-seventeenth-century plays from their readers in later centuries. In this article I explore how editors from the eighteenth to the early twenty-first century have annotated and, more generally, editorially mediated instances of seemingly gratuitous evil, such as the machinations of Iago in Othello and Edmund in King Lear. While editors in the eighteenth century are primarily concerned with semantic understanding, nineteenth-century editors seem more inclined to mediate to readers a certain emotional and moral understanding, inculcating what they perceived to be socially appropriate responses. More recent editors, by contrast, attempt to convey a fuller historical and philosophical understanding of the ‘evil' at work in the play. The editorial practices which this article proposes to trace allow insights not only into changing attitudes to fictional evil but also into what the function of literature (and of Shakespeare in particular) was (and is) supposed to be.