Due to poverty, climate change, and other factors, the world’s populations are becoming more urban. While “urban” is relative to various countries, the shift from rural to urban is happening worldwide. At the beginning of the twenty-first century, the world’s populations became, for the first time, evenly split between urban and rural. By midcentury, the prediction is that most populations will live in urban areas. It follows that where there are more people, there are also more health concerns. Richard V. Crume’s Urban Health Issues: Exploring the Impacts of Big-City Living is an eminently readable, accessible volume that addresses these health concerns.