The Urban Heat Island (UHI) is an area of growing interest for many people studying the urban environment and local/global climate change. The UHI has been scientifically studied for 200 years and, although it is an apparently simple phenomenon, there is considerable confusion around the different types of UHI and their assessment. The Urban Heat Island—A Guidebook provides simple instructions for measuring and analysing the phenomenon, as well as greater context for defining the UHI and the impacts it can have. Readers will be empowered to work within a set of guidelines that enable direct comparison of UHI effects across diverse settings, while informing a wide range of climate mitigation and adaptation programs to modify human behaviour and the built form. This opens the door to true global assessments of local climate change in cities. Urban planning and design strategies can then be evaluated for their effectiveness at mitigating these changes.