Publisher Summary In a drive for more efficient use of coal—reducing net station heat rates—and reduced airborne emissions, gasification has emerged as an alternative to combustion. The inherent possibility of pre-combustion CO2 removal at modest additional cost—as practiced on a large scale in the ammonia industry—has increased the interest in gasification for the generation of electric power. This chapter explores gasification, the conversion of any carbonaceous feedstock into a gaseous product with a useful chemical heating value. Early processes for the production of gas from coal emphasized devolatilization and pyrolysis reactions creating a gas with significant hydrocarbon content for lighting purposes. Those were the town gas processes of the 19th century. With the introduction of the incandescent mantle and the development of chemical syntheses at the beginning of the 20th century, the emphasis shifted to water gas and partial oxidation processes generating synthesis gas (or syngas), in which carbon monoxide and hydrogen are the principal components.