When Shakespeare's John of Gaunt refers to England as 'this sceptred isle', he glosses over a fact of which Shakespeare's original audience would have been acutely conscious, which was that England was not an island at all, but had land borders with Scotland and Wales. Together with the narrow channels separating the British mainland from Ireland and the Continent, these were the focus of acute, if intermittent, unease during the early modern period. This book analyses works by not only Shakespeare but also his contemporaries to argue that many of the plays of Shakespeare's central period, from the second tetralogy to Hamlet, King Lear, Macbeth, and Othello, engage with the idea of England's borders. But borders, it claims, are not only of geopolitical significance: in Shakespeare's imagination and indeed in that of his culture, eschatological overtones also accrue to the idea of the border. This is because the countries of the Celtic fringe were often discussed in terms of the supernatural and fairy lore and, in particular, the rivers which were often used as boundary markers were invested with heavily mythologized personae. Thus Hopkins shows that the idea of the border becomes a potent metaphor for exploring the spiritual uncertainties of the period, and for speculating on what happens in 'the undiscovered country, from whose bourn no traveller returns'. At the same time, the idea that a thing can only really be defined in terms of what lies beyond it provides a sharply interrogating charge for Shakespeare's use of metatheatre and for his suggestions of a world beyond the confines of his plays.