There are two main objectives to this publication. The first is to find out the communalities in the experience gained in previous studies and in actual applications of solar technologies in buildings, residential as well as nonresidential. The second objective is to review innovative concepts and products which may have an impact on future developments and applications of solar technologies in buildings. The available information and common lessons were collated and presented in a form which, hopefully, is useful for architects and solar engineers, as well as for teachers of solar architecture'' and students in Architectural Schools. The publication is based mainly on the collection and analysis of relevant information. The information included previous studies in which the performance of solar buildings was evaluated, as well as the personal experience of the Author and the research consultants. The state of the art, as indicated by these studies and personal experience, was summarized and has served as basis for the development of the Design Guidelines. In addition to the summary of the state of the art, as was already applied in solar buildings, an account was given of innovative concepts and products. Such innovations have occurred in the areas of thermal storage by Phase Change Materials (PCM) and in glazing with specialized or changeable properties. Interesting concepts were also developed for light transfer, which may enable to transfer sunlight to the core areas of large multi story nonresidential buildings. These innovations may have a significant impact on future developments of solar technologies and their applications in buildings. 15 refs., 19 figs., 3 tabs.