This ‘Little Book’ is a whistle-stop tour of ‘Energy and the City’. The book identifies ways to help cities achieve energy and carbon emissions savings through interventions in the urban environment that are not too drastic or expensive. The uses of energy in the city are complex and multifaceted, so we won’t be able to cover everything here. In this little book we make a start, using the City of Southampton as a case study. We detail some of the work we carried out for the Liveable Cities programme including city-wide studies of the refurbishment of buildings, using buildings as power generators, and aspects of residents’ choices in the context of energy. We also discuss how options under these three themes can contribute to the reduction of CO2 emissions in Southampton and UK cities.