In recent years, the extent to which contemporary societies are secular has come under scrutiny. At the same time, many countries, especially in Europe, have increasingly large nonaffiliate, "subjectively secular" populations, while non-religious cultural movements like the New Atheism and the Sunday Assembly have come to prominence. Making sense of secularity, irreligion, and the relationship between them has therefore emerged as a crucial task for those seeking to understand contemporary societies and the nature of modern life. Drawing on ethnographic fieldwork in southeast England, develops a new vocabulary, theory, and methodology for thinking about the secular. It distinguishes between separate and incommensurable aspects of so-called secularity as insubstantial - involving merely the absence of religion - and substantial - involving beliefs, ritual practice, and identities that are alternative to religious ones. Recognizing the cultural forms that present themselves as non-religious therefore opens up new, more egalitarian and more theoretically coherent ways of thinking about people who are "not religious." It is also argued that recognizing the non-religious allows us to reimagine the secular itself in new and productive ways. This book is part of a fast-growing area of research that builds upon and contributes to theoretical debates concerning secularization, "desecularization," religious change, postsecularity, and postcolonial approaches to religion and secularism. As well as presenting new research, this book gathers insights from the wider studies of non-religion, atheism, and secularism in order to consolidate a theoretical framework, conceptual foundation and agenda for future research.