Basic aspects of current solar photovoltaics (PV) are reviewed, starting from the recently developed already-on-the-market first-generation solar cells and ending with promising but not yet commercialized third-generation cells and materials possibly leading to new cell designs. The emphasis is on the physical principles of various solar cells which are divided into several groups according to our classification scheme. To make the picture complete, some technological and economic aspects of the field are discussed. A separate chapter considers antireflection coatings and light-trapping devices — structures which, while have not yet appeared in the PV review literature, are an integral part of the solar cell field.