The data obtained by observations of lightning from geostationary orbit are summarized herein based on NOAA Technical Report NESDIS 153, i.e., Geostationary Lightning Mapper (GLM) Value Assessment (VA), Lead author: Dr. Scott Rudlosky, which was published 4 years after the launch of the Geostationary Operational Environmental Satellites-R Series (GOES-R). The GLM onboard the GOES-R is the first operational lightning mapper, and the operational use of the GLM is about to begin after its initial evaluations made during that 4-year period. The benefits of observing lightning from geostationary orbit are (1) improving short-term forecasts through data assimilation, (2) improving the intensity forecasts of tropical cyclones, (3) improving the warnings for severe thunderstorms and tornados, (4) improving precipitation estimations, (5) filling the radar data gap, (6) improving lightning safety, (7) applications for climate science, (8) mitigating aviation hazards, and (9) improving the safety and effectiveness of wildfire responses. Recent studies have also demonstrated that intra-cloud lightning and cloud-to-ground lightning can be identified from satellite observations.