By 2050, world annual energy consumption is predicted to grow from the present 13 terawatt - years (TWyr) to nearly 30 TWyr. Although all energy sources must be considered in meeting this challenge, solar energy may arguably be the only carbon-free source capable of supplying a significant fraction of energy at these levels. This issue of MRS Bulletin reviews the status and future development of solar photovoltaic technologies based on inorganic materials. The discussion begins with materials and cell designs for second-generation photovoltaics based on thin films [a-Si:H, Si, Cu(In, Ga)(Se, S)2, CdTe]. Recent advances in tandem cells and concentrators are alsoreported, along with photovoltaic approaches involving nanoscale materials such as quantum dot arrays. Finally, work on transparent conducting oxides that are critical to nearly all cell designs are discussed.