The unique properties of black carbon-rich soils have only recently been recognized and international efforts have significantly increased to utilize this knowledge to improve agriculture and the environment in several ways. Biomass-derived black carbon, charcoal or "biochar", as it is nowadays called, can be used as a soil amendment to improve nutrient retention and availability and therefore increase crop yields. Such a use of biochar is a significant advance over conventional organic matter management, as the biochar is more stable in soil and is better able to retain nutrients. In combination with sustainable biomass production, such a biochar sequestration can be carbon negative and therefore be used to actively remove carbon dioxide from the atmosphere, with obvious significance for mitigation of climate change. Biochar production can also be combined with bioenergy production through the use of the gases that are given off in the pyrolysis process. This book is the first to synthesize the expanding research literature on this topic. This is all the more important at this juncture in the development of a biochar technology, as it requires an interdisciplinary approach involving engineering, environmental sciences, agricultural sciences, economics, and policy. The book provides a comprehensive overview of current knowledge of the science and technology of biochar.