Due to population growth, city administrations are starting to worry about the scarcity of natural and finite resources that are being more demanded and also services for citizens such as water, energy, transportation, health, education and security. The information technologies have been allies in the challenge of making a more effective use of these resources, presenting increasingly smaller and more present devices and enabling greater control of the systems that manage such cities. This book brings an objective method to categorize and classify cities based on their technological aspects using preliminary studies to define which criteria will be used in this classification.