Organisms are increasingly being used to assess environmental impacts on ecosystems. Lichens are among the best known, most widely used biomonitors of environmental change, with thousands of papers published on this subject in the last decades. The present book provides the most recent synthesis on this subject. It is divided into three sections: (1) Monitoring lichens as indicators of pollution; (2) monitoring lichen diversity and ecosystem function; and (3) methods for monitoring lichens. The first two sections present the state of the art in the respective fields, while the third briefly presents the methods currently used in lichen biomonitoring. Sampling design, sampling strategy, and data quality evaluation are dealt with in detail in two chapters. The first section reviews the huge body of knowledge of lichens as indicators of air pollution, including bioindication, accumulation of metals and radioelements, and the use of lichens as biomarkers. The second section covers an array of approaches to monitoring lichen biodiversity and ecosystem function, from focusing on one or a few species to monitoring the biodiversity of lichens across whole regions in terms of lichen abundance, diversity, and/or community composition. The third section presents methods for monitoring lichens, written as experimental protocols for use in other situations where monitoring is required. Readership: A wide spectrum of users in fields such as education, environmental management, forestry, biodiversity research. A comprehensive, up-to-date review of lichen monitoring, and an aid in identifying problems and pragmatic approaches to the assessment of biodiversity and environmental quality.