Urban health is the study of the health of urban populations. More than half the world’s population is now living in urban areas, and two-thirds of the world’s population will live in cities by 2030. This means that characteristics of cities—including, for example, features of the built environment—are shared by a large proportion of the global population. These characteristics ultimately shape how most of us think, feel, and behave; they shape what we eat and drink; and, inevitably, they shape our health. The ubiquity of urban exposures suggests that a full understanding of the features of urban environments that affect health—and how they do so—can unlock the potential for approaches to prevent disease, promote health, and make a substantial impact on the health of urban populations. Studying urban health therefore requires an appreciation both of the urban exposures themselves and the approaches that can inform scholarship in the field. This book combines these with case studies that illuminate the progression of health in cities, aiming to capture the current state of the field while also pushing the field, through holding a mirror to itself, to consider its next decade.