Smart zero-energy buildings and communities have a major role to play in the evolution of the electric grid towards alignment with carbon neutrality policies. The goal to reduce greenhouse gas emissions in the built environment can be pursued through a holistic approach, including the drastic reduction of buildings' energy consumption. The state-of-the-art in this field relates, on the one hand, to design methodologies and innovative technologies which aim to minimize the energy demand at the building level. On the other hand, the development of information and communication technologies, along with the integration of renewable energy and storage, provide the basis for zero and positive energy buildings and communities that can produce, store, manage and exchange energy at a local level. This book provides a structured and detailed insight of the state-of-the-art in this context based on the analysis of real case studies and applications.