For a topic that until recently was presumed not to exist, English nationalism has transformed into an apparently obvious explanation for the Brexit result in England. Subsequent opinion polls have also raised doubts about the extent of continuing English commitment to the union of the United Kingdom itself. Yet, even as Englishness is apparently reshaping Britain’s place in the world and—perhaps—the state itself, it remains poorly understood, in part because of its unfamiliarity. It has long been assumed that nationalism is a feature of political life in the state’s periphery—Scotland, Wales, and Northern Ireland—but not its English core. Another barrier to understanding bas been the relative lack of public attitudes data with which to explore the nature of English nationalist sentiment.This book draws on data from a survey vehicle—the Future of England Survey—specially established in 2011 to facilitate the exploration of patterns of national identity in England and their political implications. On the basis of these data, Englishness offers new arguments about the nature and effect of English nationalism on British politics, as well as how Britishness operates in different parts of Britain. Crucially, it demonstrates that English nationalism is emphatically not a rejection of Britain and Britishness. Rather, English nationalism combines a sense of grievance about England’s place within the UK with a fierce commitment to a particular vision of Britain’s past, present, and future. Understanding its Janus-faced nature—both England and Britain, as it were—is key not only to understanding English nationalism, but also to understanding the ways in which it is transforming British politics.