The overall objective of this book to give a self-containedin-depth discussion of the physics of thin-film systems in a manneraccessible to both researchers and students, so that the readersgain a sound perspective on the past and a foundation forprojecting future trends. It starts with a brief generalintroduction to renewable energy, photovoltaics, and thin-filmtechnology challenges.  It covers most aspects of the physicsof thin-film photovoltaic devices, including device operations,material structure and parameters, thin-film junction formation,analytical and numerical modeling, recently developed concepts oflarge area effects and lateral non-uniformities, physics ofshunting (both shunt growth and effects), and the physicsunderlying device degradation. Also, it reviews a variety ofphysical diagnostic techniques proven in thin-film photovoltaictechnology.