 Nighttime light observations from remote sensing have become increasingly important for understanding human activities and their associated environmental impacts. Advances in sensor technology, algorithms, and products have enabled more accurate and timely measurements of nighttime light levels, which can be used to track urbanization, socioeconomic dynamics, armed conflict and disasters, fisheries, energy use, and climate change. These advancements are also leading to deeper insights into the changing world through multidisciplinary and interdisciplinary analyses of nighttime light observations.