Volcanoes maintains three core foci: Global perspectives explain volcanoes in terms of their tectonic positions on Earth and their roles in earth history; environmental perspectives describe the essential role of volcanism in the moderation of terrestrial climate and atmosphere; humanitarian perspectives discuss the major influences of volcanoes on human societies. This latter is especially important as resource scarcities and environmental issues loom over our world, and as increasing numbers of people are threatened by volcanic hazards.--From publisher's description.