This chapter discusses the sociological study of religion and spirituality in contemporary society. It defines religion and spirituality, and discusses the particular features of the sociological study of religion. The chapter examines various dimensions of religious change in Australia: the decline of Christianity, the growth of world religions, and the rise of alternative spiritualities. In the 1990s and early 2000s, nature religions were among the fastest growing religions in Australia. The chapter describes how the sociological study of religion proceeds. The most well-known typology in the sociology of religion is the Christian-focused ‘church–sect typology’. A contested concept that refers to the social changes that agrarian and ‘traditional’ societies undergo to achieve modernity, such as the development of nation-states and associated political institutions based on the rule of law, secularisation, industrialisation, urbanisation, and a reliance on science and reason as the basis for understanding the world.