This easy-to-read handbook provides a comprehensive review of the current knowledge on lichens. The structure of lichens and their dual nature is explained, as well as the physiology of interaction of the symbionts. The way lichens reproduce and their ecology is included, with methods for cultivating them and their isolated symbionts. Extremely useful as a text of lichenology, this handbook will benefit students of lichenology and allied fields, those interested in symbiotic associations and ecology, and teachers of biology, botany, and ecology courses.