Perovskite solar cells based on organometal halide light absorbers have been considered a promising photovoltaic technology due to their superb power conversion efficiency (PCE) along with very low material costs. Since the first report on a long‐term durable solid‐state perovskite solar cell with a PCE of 9.7% in 2012, a PCE as high as 19.3% was demonstrated in 2014, and a certified PCE of 17.9% was shown in 2014. Such a high photovoltaic performance is attributed to optically high absorption characteristics and balanced charge transport properties with long diffusion lengths. Nevertheless, there are lots of puzzles to unravel the basis for such high photovoltaic performances. The working principle of perovskite solar cells has not been well established by far, which is the most important thing for understanding perovksite solar cells. In this review, basic fundamentals of perovskite materials including opto‐electronic and dielectric properties are described to give a better understanding and insight into high‐performing perovskite solar cells. In addition, various fabrication techniques and device structures are described toward the further improvement of perovskite solar cells. Since the first report on a perovskite‐sensitized solar cell developed in 2009, and long‐term durable solid‐state perovskite solar cell developed in 2012, power conversion efficiencies (PCEs) of over 15% have been reported. The highest PCE of a laboratory cell was 19.3%, which was developed by UCLA in 2014. Perovskite solar cells keep on surging, where better understanding of the opto‐electronic properties of perovskite light absorbers is crucial to design higher‐performing perovskite solar cells.