This introductory chapter sets out the argument and scope of the book, situating it within contemporary scholarly and popular debates about the place of religion in national life in Australia, the British Commonwealth and throughout the Western world. Two questions are asked. First, what happened during the long 1960s to the idea of ‘Christian Australia’ and ‘Christendom’, so long and widely assumed, and so quickly abandoned? Secondly, how did evangelical Christian leaders respond to this rupture? What follows is a portrait of the resurgence of interest in the connection between religion and nationalism in the wake of decolonisation and globalisation amongst historians, politicians and cultural commentators, with a particular focus on the ‘long 1960s’. Exploring parallels with declining Christian national identity in the metropole itself, the case is made for a broadening of the usual European and North American focus of secularisation studies to suggest that the ‘long 1960s’ signalled the death of not just ‘Christian Britain’, but ‘Greater Christian Britain’. A case is made for why evangelicalism, situated in Australia but connected to a broader global story, is an appropriate prism for exploring these changes, given its influence on Australian nation-building and the peculiar problems its conversionist ethos faced with the collapse of civic Protestant nominalism in the 1960s.