Lichens are a unique form of plant life, the product of a symbiotic association between an alga and a fungus. The beauty and importance of lichens have long been overlooked, despite their abundance and diversity in most parts of North America and elsewhere in the world. This stunning book--the first accessible and authoritative guidebook to lichens of the North American continent--fills the gap, presenting superb color photographs, descriptions, distribution maps, and keys for identifying the most common, conspicuous, or ecologically significant species. The book focuses on 805 foliose, fruticose, and crustose lichens (the latter rarely included in popular guidebooks) and presents information on another 700 species in the keys or notes; special attention is given to species endemic to North America. A comprehensive introduction discusses the biology, structure, uses, and ecological significance of lichens and is illustrated with 90 additional color photos and many line drawings. English names are provided for most species, and the book also includes a glossary that explains technical terms. This visually rich and informative book will open the eyes of nature lovers everywhere to the fascinating world of lichens.