The work is an attempt to chart the path of one of the world's great cities in demographic, economic, political and cultural terms. The predictive problems are dealt with as concerns of theory and method as well as human liveability. A discussion of planning as an attempt to shape the urban form is undertaken. Although comparisons are made, the focus is on Mexico City and the role of changes in infrastructure, policy and human preferences. An argument is made that the urban form will continue to dominate most functions, and we must better understand the "bull in the china shop." The mega city concept focuses on demographic and geographical size, and can not ignore questions of density, economic viability, environmental quality, cultural relevance, and political efficacy. Additionally, the impact of natural events (the 'terre moto' of 1985) and the role of planning is dealt with in this case study of Mexico City. Historical changes in the basic infrastructure of the city are followed, and an argument about how this kind of factor impinges on the future is entertained. Numerous approaches to social change are examined, especially those dealing with urban areas. Archaeological data and maps are included to give a sense of the processes involved. An underlying premise of this book is that 21st century ving must understand the lessons of cities like Mexico City. The analysis is meant to assist in the development of theory and method appropriate for this area of human living. Using historical and some statistical data, the hope is that some key extrapolations, comparisons, and bursts of insight will help us to shape the urban future that we want to live in. Stressing what we already know about Mexico City, urban processes, and the challenges of accurate prediction, the goal is to anticipate various scenarios. While the focus could rightfully be on individuals, genders, social classes, ethnic groups, and so forth, these will be duly noted.