Photovoltaic cells provide clean, reversible electrical power from the sun. Made from semiconductors, they are durable, silent in operation and free of polluting emissions. In this book, experts from all sectors of the PV community - materials scientists, physicists, production engineers, economists and environmentalists - give their critical appraisals of where the technology is now and what its prospects are. Two sample chapters - crystalline silicon solar cells and photovoltaic modules, systems and applications are now available online.