The Lepidoptera (moths and butterflies) are one of the largest groups of insects with over 150,000 known species. This is the first single-volume reference work on the biology and systematics of these fascinating creatures. Part I reviews the main body parts with discussion of their function and importance in the life of the organisms. Other chapters cover feeding, flight, migration, hearing, defense, sound production, and many other aspects of lepidopteran life. The environmental significance of Lepidoptera, summarized in Part II, is discussed in terms of larvae and caterpillars as herbivores and prey for birds, mammals, and other insects. Part III is a global overview describing biology, classification, and evolutionary relationships within and between lepidopteran groups. This book will be an indispensable resource for naturalists, professional entomologists, and conservationists for years to come.