Book excerpt: Underground Coal Gasification (UCG) is carried out in unmined coal seams, using wells drilled from the surface and converting coal into synthesis gas. The gas can be used for power generation and synthesis of automotive fuels, fertilizers and other products. UCG offers financial, social, and environmental benefits over conventional coal extraction and utilization methods and may play a critical role in ensuring energy security in the future. Underground Coal Gasification and Combustion provides an overview of underground coal gasification technology, its current status and future directions. Comprehensive in approach, the book covers history, science, technology, hydrogeology, rock mechanics, environmental performance, economics, regulatory and commercial aspects of UCG projects. The first book on the subject in forty years, it is unique in analysing more than a century of global UCG developments by experts from Australia, Canada, Poland, Russia, Ukraine, United Kingdom, the USA and Uzbekistan. - Provides researchers, engineers, industry, educators and regulators with an authoritative overview of science and practical applications of underground coal gasification technologies - Offers insight into efficiency, environmental performance, costs, permitting issues and commercial aspects of UCG projects - Written by scientists and practitioners of UCG technology sharing hands-on experience of step-by-step UCG implementation