Nowadays, thin-film solar cells potentially offer a suitable technology for solving the energy production problem with an environmentally friendly method. Besides, thin film technologies show advantages over their bulk-semiconductor counterparts due to their lighter weight, flexible shape and device fabrication schemes and low cost in large-scale industrial production. Although many books currently exist on general concepts of PV materials and devices, few are offering a comprehensive overview of the fast development in thin film Cu(In,Ga)Se2-based solar cells. “Key Developments in CuInGaSe2 Thin Film Solar Cell” would provide an international perspective on the latest research on this topic. It presents a wide range of scientific and technological aspects on basic properties and device physics of high-efficiency CIGS solar cells from the last research frontier point of view. The book was designed for photovoltaic researchers and scientists, students and engineers, with the mission to provide knowledge of the mechanisms, materials, devices, and applications of CIGS-based technology necessary to develop cheaper and cleaner renewable energy in the coming years.