Book excerpt: Modelling the City examines the changing role of urban models in respect to both the need to readdress measures of urban well-being and the perceived need to bring model outputs more in tune with key planning problems. The authors argue that whilst there has been substantial progress with a wide range of theoretical problems in urban modelling, modellers have not paid enough attention to the usefulness of their model outputs in terms of indicators which offer new insights into the workings of the city or region. Modelling the City offers a `new geography of performance indicators' for the public and private sector based on the principles of spatial interaction.