Naturalists in antiquity worked hard to dispel fanciful ideas about the meaning of living lights, but remained bewildered by them. Even Charles Darwin was perplexed by the chaotic diversity of luminous organisms, which he found difficult to reconcile with his evolutionary theory. It fell to naturalists and scientists to make sense of the dazzling displays of fireflies and other organisms. In Luminous Creatures Michel Anctil shows how mythical perceptions of bioluminescence gradually gave way to a scientific understanding of its mechanisms, functions, and evolution, and to the recognition of its usefulness for biomedical and other applied fields. Following the rise of the modern scientific method and the circumnavigations and oceanographic expeditions of the eighteenth and nineteenth centuries, biologists began to realize the diversity of bioluminescence’s expressions in light organs and ecological imprints, and how widespread it is on the planet. By the end of the nineteenth century an understanding of the chemical nature and physiological control of the phenomenon was at hand. Technological developments led to an explosion of knowledge on the ecology, evolution, and molecular biology of bioluminescence. Luminous Creatures tracks these historical events and illuminates the lives and the trail-blazing accomplishments of the scientists involved. It offers a unique window into the awe-inspiring, phantasmagorical world of light-producing organisms, viewed from the perspectives of casual observers and scientists alike.