A mosaic of mist, rainforest, and exotic wildlife: the rainforests of northern Sumatra, Indonesia’s largest and most species-rich island, are among the most biodiverse habitats on Earth. At the heart of this work is the fascinating diversity of butterflies, especially moths, documented in a systematic and detailed manner. Using a light trap, Armin Dett photographed around 1,000 specimens and then released them. Together with renowned scientists, these speciment were precisely identified and described. 

Beyond its impressive focus on insect diversity, the book also addresses the plight of the endangered orangutan. Through sensitive and insightful contributions, the orangutans' way of life and social behaviour are portrayed within a broader ecological context, as are the threats to their habitat. Thus, the book successfully combines scientific precision with vivid nature writing, serving as a poignant tribute to Sumatra's unique wildlife and a fervent call for its preservation in the era of climate change.