Oil shale, tar sands, and coal are very plentiful in North America. They are potential sources of transportation fuels to supplement or ultimately replace petroleum until renewable sources of energy can be developed. Synthetic fuels from oil shale, tar sands, and coal will phase into the supplies of transportation fuels during the rest of this century. The emerging nature of the technologies, the magnitude of petroleum use today, and the costs of building commercial plants all limit the rate at which synthetic fuels can be assimilated. One million barrels a day of synthetic fuels production by 1990 is ambitious but achievable if the governmental bodies cooperate in expediting the permitting and resolving the inevitable obstacles. Synthetic fuels can be refined to high quality transportation fuels using modern refining technology, and they can serve as substitutes for crude oil in refineries with modern hydroprocessing capability.