Book excerpt: Numerous and charismatic, the Lepidoptera is one of the most widely studied groups of invertebrates. Advances in molecular tools and genomic techniques have reduced the need for large sizes and mass-rearing, and lepidopteran model systems are increasingly used to illuminate broad-based experimental questions as well as those peculiar to butterflies. Putting the spotlight on the second most numerous order of insects living today, this book provides a summary of cutting-edge studies of the Lepidoptera as an organism in and of itself and as model systems. Leading researchers discuss symbiosis, genomes, sex determination, natural products, ecophysiology, sensory systems, pest control, the sterile insect technique, immunity, and evolution development. Understanding the biology and genetics of butterflies and moths may lead to new species-selective methods of control, saving billions of dollars in pesticide use and protecting environmental and human health, making the sections on pest control and the sterile insect technique extremely important.