Book excerpt: Consisting of presented papers from the 15th International Conference on Urban Regeneration and Sustainability, the included works address various aspects of the urban environment and provide solutions leading towards sustainability. Urban areas result in a series of environmental challenges varying from the consumption of natural resources and the subsequent generation of waste and pollution, contributing to the development of social and economic imbalances. As cities continue to grow all over the world, these problems tend to become more acute and require the development of new solutions. The challenge of planning sustainable contemporary cities lies in considering the dynamics of urban systems, exchange of energy and matter, and the function and maintenance of ordered structures directly or indirectly supplied and maintained by natural systems. The task of researchers is to improve the capacity to manage human activities, pursuing welfare and prosperity in the urban environment. Any investigation or planning on a city ought to consider the relationships between the parts and their connections with the living world. The dynamics of its networks (flows of energy matter, people, goods, information and other resources) are fundamental for an understanding of the evolving nature of today’s cities. Large cities represent a fertile ground for architects, engineers, city planners, social and political scientists, and other professionals able to conceive new ideas and time them according to technological advances and human requirements. Coastal areas and coastal cities are an important area covered in this volume as they have some specific features. Their strategic location facilitates transportation and the development of related activities, but this requires the existence of large ports, with the corresponding increase in maritime and road traffic and all its inherent negative effects. This requires the development of well-planned and managed urban environments, not only for reasons of efficiency and economics but also to avoid inflicting environmental degradation that causes the deterioration of natural resources, quality of life and human health. These research papers put a focus on sustainability across the multidisciplinary components of urban planning, the challenges presented by the increasing size of cities, the number of resources required and the complexity of modern society.