For more than 50 years, hopeful eyes have been cast at the hundreds of billion of barrels of oil locked in the Rocky Mountains'Green River formation Many abortive attempts have been made to extract the oil commercially. So far, all have failed- not technically but economically. However, the price of crude oil is going up rapidly. Gasoline shortages this past summer and heating oil shortages last winter ( and probably again the winter) are kindling interest in energy sources everywhere-but particularly, in the U.S. for energy sources that will not ruin the balance of payments. Hence, oil from shale is getting another appraisal. In this review, we cover the chemical nature of oil shale, the oil shale reserves in the tri-state area of Utah, Wyoming, and Colorado, and the production of shale oil from the oil shale rock.