Interest in the Fischer-Tropsch synthesis (FTS) has undergone periods of significant development and periods of near neglect since its discovery by Fischer and Tropsch in 1924. It was developed in Germany during the 1930s in competition with direct liquefaction. Up to the end of the war in 1945, direct liquefaction was the dominant process for converting coal to transportation fuels; in Germany the FTS was used mainly for the production of chemicals and substitutes for natural products, including butter. After 1945, the commercial application of FTS in Germany rapidly declined, although Professor Kölbel, among others, continued work on the scientific and engineering aspects of the reaction