This opening chapter introduces Desecularisation of the City by showing how London’s churches have grown since around 1980 and exploring reasons why they have done so. Then, the chapter considers the significance of such growth in wider academic and non-academic debates, entailing a discussion whether the churches of London are a ‘blip’ in comparison with the rest of the UK and with analogous cities worldwide and how London’s churches compare with other religious and secular bodies operating in the capital.