The only field guide to cover all North American butterfly species, this monumental work is also a complete natural history, fully describing the biological and ecological world of butterflies in general. It is without question the most important book on butterflies in several decades, and the most complete treatment of a major butterfly faun ever published.

The book is written at several levels of detail, most of it accessible to anyone, and employs the minimum of technical terms necessary for ensuring scientific accuracy. Extensive introductory material—a book in itself—stresses butterfly biology and ecology: structure, flight, metamorphosis, hibernation, physiology, roosting, migration, mating, egg laying, intelligence, social behavior, larval and adult foods, enemies, mimicry, variation, evolution, habitats, distribution, and conservation. The main text is arranged in phylogenetic sequence, and characteristics or behavior common to all members of a family, subfamily, or tribe are discussed at those levels. The skippers, a large group often excluded, are treated in full.

Several unique features make identification easier and more certain than with any other field guide. First, every species (and many subspecies) of butterfly ever recorded north of Mexico (or in Bermuda or Hawaii) is treated at length and illustrated in color. Over 1,800 butterflies representing all 679 species (males, females, uppersides, undersides, subspecies, etc.) are illustrated on 42 full-page plats. Another 136 color photographs illustrate the various life forms in natural habitat: eggs, larvae, pupae, and the more familiar and more spectacular adults.

The author also provides a catalogue listing all known host plant genera and the specific butterfly larvae that eat them; techniques for collecting, raising, and studying butterflies; bibliographies of the most useful plant books and other sources to further the study of butterflies; and an index of all common and scientific butterfly names and all technical terms taken up in the text.

In short, this book is indispensable for pursuing a hobby or scientific interest in butterflies.