The subject of this book is religion and identity; not only national identity in the way that Professor Colley has dealt with it in her recent study of the Britons, but also regional and local identities. Within that framework my interest is in trying to penetrate to the heart of vigorous religious and political cultures, both elite and popular. My chronological boundaries, in the main, will be the long eighteenth and nineteenth centuries when the interaction of religion and identity was a vital ingredient in the religious, social and political history of the British Isles, but I shall also say something about how that pattern was eroded in the twentieth century. Foolishly, perhaps, I intend to deal with all parts of these islands at some point in their history, and to try to bring to life a diverse and variegated spectrum of religious communities from Argyll to Armagh, from County Cornwall to County Clare, from the Welsh valleys to the Scottish highlands, and from Birmingham to Belfast. Much is based on my own research over the past decade, but much more is dependent on a great number of distinguished historians of the four nations and beyond whose work can only gain from being brought into a closer relationship with one another than has customarily been the case. I am glad to record my debt to them right at the beginning as well as in the conventional way through the notes, which, for the sake of accessibility, will be kept to a decent minimum. They nevertheless reflect, in a small way, the healthy state of the writing of religious history in these islands.