Switchable windows can be used for a variety of applications including architectural and vehicle windows, aircraft transparencies, skylights and sunroofs. Related to glazing are applications for low-information content displays for the display of information. Switchable windows rely on a variety of processes and materials. Several companies throughout the world are developing dynamic glazing. University and National Laboratory groups are researching new materials and processes to improve these products. Switchable glazing for building and vehicle application is very attractive. Conventional glazing only offers fixed transmittance and control of energy passing through it. Given the wide range of illumination conditions and glare, a dynamic glazing with adjustable transmittance offers the best solution. This study covers selected switching technologies including, electrophoresis or suspended particles, electrochromism, liquid crystals, thermotropism and gaschromism. Currently much development in switchable devices is aimed at deposition processes suitable for glass substrates. In the future, there is movement towards plastic substrates for weight savings. Cost of production and defects in large-area deposition are two of the largest issues. These exciting technologies create many challenges and opportunities for glass and plastic companies along with excitement for building designers.