Book excerpt: Conventional building skins are constructed as static structures upon the typical design conditions in terms of external climate and internal occupant activities. This generates dissociation between the envelope structure and its environment. With the emerging advanced materials, such as chromic-based materials, spectrally selective coatings, and transparent photovoltaic, more dynamic and smarter building skins are now achievable and constructible. This book updates readers on the key areas of smart building skins embodied in the novel advanced materials with unique structures and smart properties that enable multiple functions in energy efficiency, solar harvesting, and environmental greenness. It synergistically integrates the topics and knowledge of material design and experimental studies, theoretical analyses of building energy-saving mechanisms and solar energy utilization, and new design methodologies and processes taking advanced materials into account at different scales - from nano to the macroscale.