This book represents a compilation of research in sustainable architecture and planning. Its main focus is offering strategies and solutions that help reducing of the negative impacts of buildings on the environment and emphasizing the suitable management of available resources. By tackling the topic of sustainability from a historical perspective and also as a vision for the future, the book in hands provides new horizons for engineers, urban planners and environmentalists interested in the optimization of resources, space development, and the ecosystem as a whole to address the complex unresolved problems our cities are facing. This book is a culmination of selected research papers from IEREK’s sixth edition of the International Conference on Urban Planning & Architectural Design for Sustainable Development (UPADSD) held online in collaboration with the University of Florence, Italy (2021) and the first edition of the International Conference on Circular Economy for Sustainable Development (CESD) held online in collaboration with the University of Salento, Lecce, Italy (2021).