Coal gasification peaked in activity during the 1920s with a large number of U.S. plants making low-BTU gas by fixed-bed gas producers. In some cases, these plants prepared hot raw gas for firing open hearth furnaces and, in other cases, the gases were cooled, scrubbed, and desulfurized for various utility and industrial purposes. Efficient production of clean, low-BTU gas from coal was clearly demonstrated on an industrial scale. However, the technology was not advanced to a point which allowed this gas to later compete with low cost hydrocarbons. Improvement of producer performance could allow gas producers to have strong growth potential in modern economies. Two aspects which deserve attention from research and engineering are (1) capability of utilizing lowest cost coals and (2) capability of enlarging producer gasification capacities.